This video should be put on Stihl's website and you be well paid for it. There is no way a corporation could put out a video like you have done, it would have been cheezy as hell and would be hard to understand. Thank you for taking the time to make this.
Great Vid Tom. Only change I would add is I allow a 5 minute warm up, especially in the winter and in freezing conditions. Also, these mixtures will vary with changes in temperature, humidity, and elevation (0xygen content in the air). Don’t be surprised if you used this procedure on a hot summer day and then in the winter when you want to use the equipment it starts acting funny. Again great content Mate!
Agree re. the warm up mate, though I wanted to share their exact process, they specifically mention the 1 minute varying rpm. My opinion is an engine is best final tuned when fully heat soaked. This can take a good 5 minutes or more of use / fully loaded! Yes, frequently tuning a 2 stroke is an important part of ownership. I’ll often tweak my carbs each time I take them out, even on the same day!
@@jpol3808 Carbs don't run well in any weather. That is why modern engines have gone to systems that can adjust the combustion on the fly. As conditions vary to get the best performance you will need to adjust your carb. Granted on lawn equipment we aren't generally racing them so it doesn't matter much if your conditions aren't changing drastically.
@@NONO-hz4vo Yep your correct. Direct computer controlled fuel injection is the way to go for any condition and any style of driving. Groceries or racing. It handles all situations. I was just helping the guy out with a tip on running his carb equipment on the choke slightly longer in cold weather to richen up the mixture while it's warming up. That saves having to play with the adjuster every time the weather changes on you. Later!
I had just watched your video about the accelerator pump I didn't know existed in my Walbro on my Poulan chain saw. I checked and it was in very good condition so I just made sure the passage and bore were clean and reassembled the carb with new gaskets and needle and lever. Now you explain this settings so that it is easy to follow and it works. Thanks for doing these videos and sharing your knowledge with us. I'm almost 80 and have worked on a lot of different engines both gas and diesel. It is clear instructions like you give that makes things easy if people just try.
Fantastic Lloyd! Always great to have people like yourself here who grew up and lived when repairing was the norm, rather than the throwaway society we’ve become. Great to hear that at 80 you’re still passionate about engine repairs. Welcome to the channel :)
The critical factor that helped my understanding was to remember that lubrication is mixed with the fuel, so lean delivery is dangerous to the cylinder wall. So, for both H and L, this tuning algorithm is set up up to run a little on the rich side to ensure adequate lubrication and slower rpm. The second point is that when you're on the rich side of the equation, increasing fuel delivery consistently lowers rpm. I love your remark about building in a little reserve to that setting. So, when fuel changes, air filters are clogged, and ambient temp changes you've got reserve that prevents the engine from creeping into that territory of lean cylinder wall damage. I guess this is also why environmentalists don't like 2 strokes, since perfect stoichiometric balance is too close to the threshold of engine damage.
You probably are unaware, that Every piston is cooling (regulating the temperature) with the "vaporisation heat" from the Extra fuel on Top Rpm. So, with that added fuel, you actually Cool the piston, so, that it does Not Overheat and later start even to seize into the cylinder walls , consequently damaging them. And, because of that extra fuel added at max Rpm, the environmentalists don't like the 2 strokers, beside the added oil in the fuel 4 the lubrication.
KTM has been working to keep their 2 stroke bikes compliant in Europe and has gone to fuel injection. Just isn't possible to have a mechanical carb with one setting be able to burn efficiently across so many variables. For small engines though carbs are cheap, easy, and reliable. Maybe someday we will have some sort of hydrogen burning engine but by then who knows if there will be supercapacitors that run motors with 10x more power than we get out of engines.
Actually this brother is the first one i have heard so far, about how to properly explain the proper tuning of these membranic carburetored engines. Thanks to brother Tom.
Would also recommend Tom's 'how to tune a chainsaw' video from July 2021 which follows this procedure, but without the tachometer and with no technical jargon. For me, it is the best tuning video on YT, by a country mile.
I have never worked on small 2 stroke engines but I have rebuilt more than my share of automotive engine carburetors and I enjoyed watching. These carburetors are much simpler than an automotive carburetor.
This is just the video I needed, I have a 2 stroke Husqvarna 128ld string trimmer and have replaced it with three, "NEW" different carburetors with the same results. On a cold start it starts perfect, but at half choke it idles very, very high which is NOT normal. After I take it off choke it idles normal, it rev's up perfect, the idle mixture screws are set perfect but when the engine worms up and I pull the trigger, then release the trigger it idles between 3700 and 4000 rpm's. The idle speed for this model trimmer is between 2300 and 3200 rpm's, and 3700/4000rpm's is to high with the trimmer head NOT spinning. Now, if I let it set and idle at 3700 rpm's for maybe a minute or two the rpm's will start to drop then it will shut off. In other words, I can't get it to idle at the normal idle speed without it keep shutting off. Parts Replaced: Fuel lines and fuel filter New Spark Plug Three NEW, different carburetors and gasket Also a new air filter Intake and gasket My question, would a ignition coil cause these symptoms or what would you suggest I try next?
It doesn’t really sound like an ignition issue to me! I’d check the piston skirt through the exhaust port to make sure it’s not scored. Then do a pressure and vacuum test :)
What a great in-depth explanation and attitude. I don't normally sub to people doing random videos ill only need help with for a moment. You are an exception. And to me that is saying something
Thank you, I've been doing it this way for many years bit this spelled out exactly why and actual steps that I never really thought through...thanks again
Even though I don't own a Stihl, I watched this twice to better understand. This makes a lot of sense now that I understand basics. At some point a similar video for Husky would be more helpful for guys on the other side, ha ha.
Hey! It’s literally identical! It’s the EXACT same process :) I understand it can take a few viewings to get your head around it, but I’m glad it makes sense!
EXCELLENT video and very well articulated. Loved it and it helped me tremendously but I am left with one question! When adjusting the H RPM of the my 455 Rancher, the specs show… Maximum power speed 9,000 rpm Max engine/motor 13,300 rpm Which value am I supposed to adjust it to (less the 500rpm for safety measures)
Just tried several videos and this is the one that worked on my 201T and 461R. However, even with my H set all the way counterclockwise I still think my max rpm is a tad high. My Tach was one off of amazon and couldnt get a solid read of the high rpms as it jumps quite a bit past 9000rpm but still seemed a bit high. Either way, thank you a ton for this video as it is the only one that took care of 95% of my issues.
Gosh Dang - a nice running 2 cycle is a dream - great explanation - you really have to be patient with the adjustments - one screw up and you can kiss your shoulder joint goodbye with endless pulls on that nasty jerky little engine - Back in the 70's there were little 2 cycle snowblowers that would never start - of course our 'schools' were worthless to teach us what you just did and so we could never figure stuff out - all that youthful energy just wasted - Now - I ALWAYS run my engine gas out to keep that carb clean - since these little 2 cycles have little tiny ports that varnish up quite easily
I love your videos! I’ve worked on my own small engine all my life. I’d like to get a tachometer like yours but the PET2100DXR is so expensive. The 2000DXR is less than $30. Is it as good? I’m 73 and don’t want to spend over $100 Thanks Paul V
Thank you! Is that the one with a red strip around the face of the tach? If so yes, it’s excellent and for all intents and purposes, it will do everything this one will :)
Hey Tom! I keep coming back to these videos to help take my two stroke work to the next level. I have a couple of specific questions about tuning that I can't find the answer for anywhere and I'd love your help. 1. How does an ignition coil with a RPM limiting circuit affect the tuning of the high speed screw? 2. I work on a lot of carburettors (Walbro RWJ-5) with a partitioned Venturi, where the top half pulls in air only and the bottom half pulls a rich fuel air mixture. Are there any special considerations to make when tuning this type of carb?
Hey :) tuning a limited saw with an ignition limiter can be tricky as it can make you think (incorrectly) that it’s still too rich (they sound similar) and therefore lean the h screw out too far. Have a watch of this video I cover ignition limited coils and tuning them here :) ruclips.net/video/sY14oNCXvrw/видео.htmlsi=Wr5S21OS-OhyCnn3 Re the strato charged engines, no there is no special considerations, though keep in mind they do tend to run a bit leaner / hotter as the incoming charge that chases the previous spent exhaust gasses doesn’t have any fuel and it’s the fuel that does most cooling (far more than fins). Hope this helps,
@VintageEngineRepairs Very helpful thank you. I had no idea that fuel helps dissipate heat and even just knowing the term Strato charged engine helped me find some other useful videos too. I'll check out that video you mentioned about tuning with limiters now too. Thank you very much!
Can anyone with official Stihl service manuals confirm if this procedure is still current? Mainly curious if this exact method applies to their 4 mix equipment? Or are their slight differences in their procedure and RPM's now? Well done and thorough video!
Hi Tom. A good clean description. Thanks. And yes it did help. In the absence of anything else, do you use this procedure for other manufactures 2 stroke engines?
Here in the uk we seem to have some variability in the fuels depending on where you buy from. This variation seems to mean that you can get the tools adjusted right, get another mix of fuel and the tools are difficult to start or die at tickover or tricky to rev up. Have any others found this variation or do most use premium 'proper' petrol (gasoline)? Thanks for some great informative videos.
Yes, I have heard of that before, I’m not surprised to hear it. I’ll often spend 20-30 seconds tuning my machines each time I take them out, though I’m very picky and want them running optimally!
I tune by ear free spinning and then tweak it under load, and it always ends up being a little rich without load. That's my target. People talk about altitude and temp quite a bit, but it's going to be a rare case where they take it out of the climate they bought it in. Nobody goes on a world tour and buys a chainsaw as a souvenir. 🤣
Most people here cut their firewood when its 70-90 degrees out but when winter hits and its 0 degrees out and they need a few logs cut they expect it to run exactly like it did in the warm weather and it won't.
Bill a trimmer I can see as you wont use it in the winter but Tom used a chainsaw as an example. Also I use a handheld leaf blower to blow snow off the cars in the winter and I have to tweak the mixture a little when the seasons change.
You did a Stihl trimmer carburetor adjustment video awhile back, if I'm not mistaking. If you did, can you share that link with me, there was one part in the trimmer video that you didn't cover in this one. I just bought a "NEW" carburetor for my trimmer, and need the other video to make one final adjustment, if it's not defective, before returning it for a replacement.
Hey :) what timing! I have a strimmer carb tuning video coming out shortly!! I have done one in the past, but no where near as good as this will be. Have a look back through my videos and you’ll find it :) I say hold off as the other will be released fairly soon!
@@VintageEngineRepairsHusqvarna 128ld (manufacture Idle Specs 2300-3200 rpms): This is a "New" carburetor I purchased for my trimmer and after I installed it, it was idled way to high above 4200rpm's. So I try to keep my trimmer idle speed between 2800 and 3200 rpm's, so when I adjusted the idle screw to bring it down to my idle specs it keeps shutting down and I don't want to have to continue idling it every time I use it. So do you think I should continue playing around with the idle L screw and idle screw or just return it for a replacement. Which I don't want to ship it back because I need my trimmer......
It's a shame that Honda don't tell you since they preset it at the factory which is why I reused the original carburettor when I fitted the Chinese clone Honda GX35 engine onto my dads Honda UMK435 brush cutter attachment. I am sure that I had the carburettor adjusted to its"sweet spot" using the low speed mixture adjustment screw but it kept stalling after I let the throttle off from wide open throttle & it wouldn't idle during a cold start. You told me that it could be because the high speed screw needs to be turned in a bit but I still need to check things such as the metering valve lever to see if it's set to the correct height & also that the 1 way check valve underneath the lever for the needle in the metering chamber is closing off when air or carby cleaner is applied to it from underneath the metering chamber. If I need to adjust the high speed screw then I will need to remove the brass sealing plug on the side of the carburettor which is covering the high speed mixture adjustment screw.. I have refitted the original OEM Honda GX35 carburettor for that reason, even when I was able to restart the engine again when it was warm after it stalled it wouldn't idle until I adjusted the low speed mixture screw again. That's why I thought that the check valve inside of the carburettor was sucking air into the metering chamber through that check valve which may not be closing off !
I use an old Bike shifter lever with cable to control the choke since I live in Northern Ohio where we can have 30 ish F and 90ish F - so I find controlling the choke is nice but not possible with a Back pack blower - so with a Choke control near my hand I can adjust the carb knowing that I can adjust adjust the choke if (in Autumn) we went from 73 degrees Monday to 39 degrees Tuesday -
Very interesting! It’s not an ideal way to do it, best you just tweak the carb with a screw driver and let it breath in the correct amount to get a full cylinder charge :) I will tune my equipment multiple times a day depending on changes in temp or altitude. It’s not really necessary for most people, but I like my engines to run where they are best.
@@VintageEngineRepairs I went on your channel and then saw all the 2 cycle stuff - had I known that I would have kept my caveman method on the down low - For me it's a practical solution and I can just edge that choke controller an itsy bitsy bit to get that blower into some high sonic rev's - but what would be nice as per your advice to properly adjust the needles or to have a servo controlled needle adjuster with an RPM device - oh and also a 'cordless drill' type starter motor for the backpack blowers would be good - thanx for the replys
@TotalFreedomTTT-pk9st haha no not at all, we all do what we want, it just wouldn’t feel right if I didn’t mention a quick tweak is normal and you’re not the only one so don’t feel like you’re doing anything wrong :)
Brilliant mate........thanks for being so clear and concise. My engine tach has a wire that you wrap around the plug lead. I changed it to a crocodile clip for ease of use. I'm just wondering if this type are as accurate as the ones like yours? Cheers bruv!!
@@VintageEngineRepairs Okay......so do you think adding a crocodile clip to the wire may have affected accuracy? I just thought that winding the wire around a lead was a faff......much easier to clip it on!!
Appreciate your guidance and will try again maybe I’m turning to fast. I don’t have a rpm gauge, did you have a link? The LA screw, didn’t seem to do anything do you screw that in all the way and then out 1 1/4 turns also? How do you know where it should start from or doesn’t it matter? When I quit it wouldn’t stay running also I have replaced the carb.
Great info Tom on a very popular issue! Speaking of Stihl tachometers, mine seams to be acting up. Is there a hack to replace the battery? 😁 I never thought I would have to deal with this! 😭
I have a Stihl KM-56 Trimmer. It has spark, new tune-up kit and carburetor. All fuel lines and tank vent line were tested. Muffler and spark arrestor screen clear and clean. Compression test and pressure test all passed. Stihl won't start! I'm confused! What could be a possible issue? Thanks and I have learned so much from your great videos!!
Hey :) I’d recommend putting a teaspoon full of gas and 2 stroke mix directly into the throat of the carburettor. Then make sure choke is off, ignition on, go full throttle, and pull the cord a number of times. Let me know if it starts, runs then stops after a few seconds :)
Great video Tom! I understand the process to get L & H screws set, but unless I missed it, I don't recall you saying anything about dialing idle back to spec rpm. Sorry if this is obvious, but should idle be left at spec + 500 after H screw is set, or does it then get reset to spec rpm with idle screw?
Hey :) I covered it haha, when you find fastest rpm on L and it stays at spec + 500, then richen it by 500rpm with L. Thanks for watching and commenting :)
Thank you for your brilliant video can you set the butterfly on carburettor between the idle port and first progression hole by eye with carb of and tune low speed screw and achieve same result ?
Thanks :) na you can’t, even 1/8 of a turn is a lot on the LA and you can hardly visualise that. There is quite a range between the idle drilling and progressive.
One small issue with the recent models is the speed limiter in some of them. To the novices when the limiter kicks in they might think the engine is four stroking and keep leaning out the H.
@@VintageEngineRepairs I am a self taught repairer and what you say here is what I do by instinct . Sharing it with several younger guys here in India. Thank you
This is a good video but I have one problem with their recommendation. Lets say desired speed is 10,000 and the tach shows 9,000 because they already have it so lean it won't reach 10K. Now they turn the screw in to lean it out and raise rpm but don't get the desired results. At least with the low speed you find the sweet spot and adjust from there. I don't like recommendations that just have you read a tach because the magic number your looking for occurrs twice-once on the lean side of the hump and once on the rich side. Does this make sense?
Hey Scott! I must admit I have never had a 2 stroke that I couldn’t reach their max rpm on the H screw? Maybe I’m miss understanding your comment? There are a few changes I personally make to their lean drop off tuning procedure, but for continuity of the process I didn’t add in any of my own preferences on this vid 😂 Edit: Ahhh I think I understand you!! Yes, if you go too lean you’ll eventually hit that number again. I haven’t tried it, but I don’t imagine that on the lean side, it will hold the set rpm. It will lean out and die? Maybe I should give it a go!!
@@VintageEngineRepairs Yes you got it. The point I'm making is that if an average guy just throws a tach on it and turns screws till he sees the right number, he hasn't necessarilly set it correctly. I've had saws come in where guys have done exactly that.
Scott, I adjust the high speed screw to just get 4 stroking out of the wood, so it cleans up in the cut. If the tach shows its off (too high) i may richen it a little, but I adjust to ensure good pulling in the wood.
As far as it goes, your video is good, and very helpful - but as I said, as far as it goes. I say this, because I have a Stihl FS 120 Bushcutter (circa 2002 manufacture), which ONLY has 1 adjusting screw - the Lo + and -. Even Stihl support was unable to give me a part number for it. Does anyone out there have any ideas which carb it might be ???
Would you reccomend doing this without a tachometer? just by 'feel'? Cant afford the £150 for a tach right now. Many thanks for the informative and easy to follow video btw.
Hey, yes, I go by ear most of the time and just confirm with a tach, but I only recommend it if you know what you’re listening for. Otherwise you’ll likely cause yourself problems!
Hang on now... there is no way you can do this stihl method without measuring rpms. No one can know what 3000 rpms sound like. It's the target point... you can't know if you are too high or too low without a tach
@@normanbfifteen3468 by ear, when you know how, is far more accurate than shooting for numbers, every engine is different, even if it’s the same model, numbers are an accpectable range to be in. Using your ears you can tell exactly how the engine is running and where it’s happy. The spec rpm’s are a rough guide acrosss the board, for a brand new, non broken in engine with good soft diaphragms, clean filters, sharp chain etc and will be fine, but as an engine wears in, filters may be a bit blocked, the chains not quite as sharp etc, being able to adjust an engine based on how it sounds is really the best method. Also, I can be almost if not, spot on by sound. Just like you know when your car is at 2,000 rpm, 3,000 rpm etc, you build up an audible “picture”. Just like you know when to change gears, you don’t look at the rev counter; you KNOW when the engine wants to change. It’s a similar principle here with these engines.
@VintageEngineRepairs I just started scrolling ebay and found one for 40 bucks so thought bugger it I might as well get it . I have 4 carbs to replace on some old equipment of mine so it will see some use . Great video btw , 👌
@@grahamjones4294 yes you want 21:42. Keep pressing the mode button until you get to the screen that starts with a capitol letter “P” followed by numbers. When you get to that screen, press the set button until you get 21:42. Then you can just leave it alone. Bring it next to an engine and it will register both 2 and 4 stroke engines that fire every revolution (all single cylinder ope)
Sorry to be a total idiot but do I hold the mode button down or continually click it. I either get 0mins if I click or 7760rpm if I hold the button down.
Hey mate yes it’s inductive :) here is a similar one to what I use, just way cheaper. The only difference is this one doesn’t do quite as many cylinders - totally unnecessary for any ope! Save your money! Engine Tachometer - amzn.to/3TE48GZ just for full transparency this is an Amazon affiliate link - I may earn a small amount from qualifying purchases :)
You do have any idea what is wrong in my fs38. I put brand new gaskets in carb and changed spark plug. It hardly runs idle when L and H are closed. Immediately when i open L it will stall. If i pump on top of the carb it keeps running.
Hmm pumping on the carb keeping it running indicates a fuel supply issue. I’d double check your work, pressure test the fuel lines, filter, tank vent and carburetor. Check your don’t have any air leaks in the mounting area between the carb and the engine either
@Tom I think your video was good but needed to be watched several times. Your chapter settings really help. I got confused by your different terms and the way you changed between them when you speak. Though you can get it from the video, you use a lot of terms interchangeably without realising it because you are experienced. It may be better to give a list of the different terms at the outset and then just use one term in the description of what you are doing in terms of names for the screws, speeds and alteration of the screws (clockwise[right,turn it in, lean it out], anticlockwise). Meant to be constructive as your video is good, but could just be a bit easier for certainly me to understand if you used less terms and maybe set out the alternative terms at the start
Hey! Thanks so much for the great feedback. I couldn’t agree more and you won’t see a recent video of mine like this one. Now days I plan all my tutorial videos out in a scrip so nothing gets missed or miss communicated! Thanks again :)
Great Video. I have a SH55 blower and I see the idle rpm is 2800, but there is no max rpm in the manual or online for that matter. Would you know what the max rpm should be? Thanks for sharing.
I just got around to adjusting the carb and no matter what I did I couldn't adjust it properly. Could be because its a Chinese carb. I have ordered another carb, let see what happens.@@robsteinhaur221
Here's one for ya, my kid was playing with the idle screw and screwed it all the way in , not while running though, how do I find the idle setting again , it must have been turned in 5-6 times. Would I turn in all the way, then turn back all the way , then turn in half way ???
On my STIHL BG 56C Air Blower, I have a problem starting it. I have to push the carburetor bubble about 50 to 100 times before it will get gas inside the bubble then it will start. I have replaced just about everything and no luck on starting it normally. What should I do ?
Stihl 025 Let's see if I get this proper New and proper fuel mix and full. Fuel filter not blocked. Air filter clean. Exhaust clean. Spark arrester clean. Spark plug and gap proper. Oil resivuor full. Chain proper tension. Sharp. Before factory reset: Turn the H & L to seet in the "IN" position (clockwise till it won't go any further-gentle). Factory reset: Then turn the H & L "OUT" (counter clockwise) one turn. Start it. Let it warm up one minute at different rpms. What is the factory reset for the LA screw?
I set every two stroke carb to 1.5 turns out on both jets. This should get the piece of equipment running and I tune it from there. I warm them up for five minutes before adjusting the jets.
Worth noting, the engine will be just as hot at 60 seconds as it will be at 5 mins UNLESS you’re actually putting the engine under load. If you’re just letting it idle and gently blipping the throttle a few times every so often for 5 mins you’re wasting your time. It’s not until you are actually using the engine under load that it’s going to get hotter. Air cooled engines heat very quickly.
@@VintageEngineRepairs that is what the Husqvarna Service Manual says. I do not know what the Stihl Service Manual say, so I go along with what Husqvarna said. I looked over the Instruction Manual for the 021, yesterday, and Stihl does not provide an RPM for idle or Max rpm, so I will go along with what I know. I figure 2,700 and 13,000. What do you think. A lot of their saws list 13,500 for max rpm, but I never figure that high. I had a brand new MS 170 that was turning 14,500 but not any more. I richened it up to 13,000 and change. They say you cannot adjust the H on theses saws, horse crap h- you can. There is a very small torx socket in the H jet. I just richened mine up a 1/4 turn, down to 13,020. I could have turned it out a bit more but left it where it was. 13,020 is not alarmingly fast to me.
@@VintageEngineRepairs I haven’t thrown the tach on the 021, yet, but will keep those figures in mind. It’s has new bearings, seals, piston and cylinder on it. I wait until things get broken in before I set the carb. It has a nice little four stroke on it, now, so it is ok. 11,500 is kind of low for a Stihl. My 260P will turn 13,500 easy. I am not worried about it turning to high an rpm with a 18” .325 chain on it. What I like about it is it’s easy of starting - 2,1P every time. Three pulls and your going is great for a Stihl saw. I can’t wait to see how it acts in real cold weather.
Found you looking for a solution to a chain saw problem. I have a Stihl 032 AV that I have owned since new. The trouble I’m having is that it will start and idle fine but bogs down and stalls when I pull the trigger. Fuel is new and I don’t see any obvious holes in the fuel line or pulse line, fuel filter is new. There isn’t a spark arrester just a muffler. The only work I have ever done on this saw is a carburetor rebuild kit a couple of years ago. The saw was running strong up to a few weeks ago. Any thoughts?
Hey, could be many things, but essentially it’s lean on the progressive idle drillings. Try opening the low screw 1/4 of a turn (you may have to turn the idle screw in to compensate and bring the revs up).
@@VintageEngineRepairs that worked well! It now runs and cuts but still has some power issue. I can tell it isn’t putting out all the horsepower it used to and will stall now in hardwood like walnut.
It seems as if Stihl's aim is to set the butterfly open as far back as possible at the first progressive drilling, with plenty of fuel flowing out of the 3 idle drillings.... So that when you hit the throttle the butterfly is already well opened and has little distance to travel to WOT. Add the fuel from the 3 rich low jets as well as the high jet and it is no wonder it picks up instantaneously. It is like a gun that has the trigger cocked -vs- having to cock the trigger before firing.
Hey :) fuel flows through only the idle drilling at idle - air actually flows into the progressive idle drillings from the high pressure choke side and form an emulsion with the fuel. It’s not until the butterfly is progressively opened that fuel flows out of the progressive idle drillings.
What I worry about using break fluid to soften rubber is how long will it stay soft once exposed to gas. Nags has a tendency to harden rubber and I think it will get hard, again, in short order. This is why I replace diaphragms instead of trying to rejuvenate them. I do not like to have to go back in a carb, again, for the same reason. A fools errand.
a stihl bg50 has limiter caps, where does stihl have the oem settings at before the caps are installed? or do they have a spec where the L and H screw are installed before adjustments starts before the limiters are pushed on, I do not have a service manual to look this up, thank you
Hey :) this is more expensive than stihls tach, this one is about $350 Australian dollars. It’s called a pet2100DXR. I have heard the tiny tach or fast tach are quite good and are cheaper :)
How should or what is the factory setting for the idle screw? I looked up BR400 manual and it does not say what the L&H are set in the factory, maybe what you know is as a Stihl Tech you have access to the info. Can you tell me where to start?
Hey, just to confirm, I’m not a stihl tech! I don’t want any misunderstanding there :) start at 1&1/4 turns out on both L and H and start from there. Use 2800 as your idle. So… 1). 1&1/4 on both screws 2). Start machine 3). Let it warm up for 60 seconds (adjust La if it won’t idle) 4). Adjust LA screw to 3,300 5). Turn L in and out to find fastest rpm If fastest rpm isn’t 3300 (+/- 200rpm) adjust LA screw to 3300. 6). Turn L in and out to find fastest rpm again, it should be at 3300rpm (+/- 200rpm) if not repeat adjusting LA to 3300. 7). Turn L screw anti clockwise to set rpm to 2,800. 8). Go to full throttle and turn H until you get fastest rpm. 9). Open H screw 1/8 of a turn anti clockwise to richen the mixture. Tuning complete!
Explain stihl fs55. Max.engine speed (rated) 9500rpm. Max.output shaft speed (cutting attachment) 7700rpm .which one of these rpm the H speed is to set
When the machine isn’t under load it should be set to run around 9500. However because you’ll be cutting grass, the engine will be loaded because of the resistance of the grass so it won’t ever run at 9500, it will be at around the 7500 rpm in use. Tune to 9.5k if that’s what the manual says max rpm.
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This video should be put on Stihl's website and you be well paid for it. There is no way a corporation could put out a video like you have done, it would have been cheezy as hell and would be hard to understand. Thank you for taking the time to make this.
You’re very welcome :) they don’t want people touching the screws, they’d rather you pay a technician!
@@VintageEngineRepairs You are spot on. Thanks again
Great Vid Tom. Only change I would add is I allow a 5 minute warm up, especially in the winter and in freezing conditions. Also, these mixtures will vary with changes in temperature, humidity, and elevation (0xygen content in the air). Don’t be surprised if you used this procedure on a hot summer day and then in the winter when you want to use the equipment it starts acting funny. Again great content Mate!
Agree re. the warm up mate, though I wanted to share their exact process, they specifically mention the 1 minute varying rpm. My opinion is an engine is best final tuned when fully heat soaked. This can take a good 5 minutes or more of use / fully loaded!
Yes, frequently tuning a 2 stroke is an important part of ownership. I’ll often tweak my carbs each time I take them out, even on the same day!
Hi, Where did you get the Tachometer. Thanks
That's why most every piece of equipment has a choke adjustment. Use that until it heats up and runs well in any weather.
@@jpol3808 Carbs don't run well in any weather. That is why modern engines have gone to systems that can adjust the combustion on the fly. As conditions vary to get the best performance you will need to adjust your carb. Granted on lawn equipment we aren't generally racing them so it doesn't matter much if your conditions aren't changing drastically.
@@NONO-hz4vo Yep your correct. Direct computer controlled fuel injection is the way to go for any condition and any style of driving. Groceries or racing. It handles all situations. I was just helping the guy out with a tip on running his carb equipment on the choke slightly longer in cold weather to richen up the mixture while it's warming up. That saves having to play with the adjuster every time the weather changes on you. Later!
You have a talent for explaining thing's.
Also nice to see someone laughing and smiling as much as you do.
Keep up the good work
⭐⭐⭐⭐⭐
Such a lovely comment, thank you!!!!
I had just watched your video about the accelerator pump I didn't know existed in my Walbro on my Poulan chain saw. I checked and it was in very good condition so I just made sure the passage and bore were clean and reassembled the carb with new gaskets and needle and lever. Now you explain this settings so that it is easy to follow and it works. Thanks for doing these videos and sharing your knowledge with us. I'm almost 80 and have worked on a lot of different engines both gas and diesel. It is clear instructions like you give that makes things easy if people just try.
Fantastic Lloyd! Always great to have people like yourself here who grew up and lived when repairing was the norm, rather than the throwaway society we’ve become. Great to hear that at 80 you’re still passionate about engine repairs. Welcome to the channel :)
The critical factor that helped my understanding was to remember that lubrication is mixed with the fuel, so lean delivery is dangerous to the cylinder wall. So, for both H and L, this tuning algorithm is set up up to run a little on the rich side to ensure adequate lubrication and slower rpm. The second point is that when you're on the rich side of the equation, increasing fuel delivery consistently lowers rpm. I love your remark about building in a little reserve to that setting. So, when fuel changes, air filters are clogged, and ambient temp changes you've got reserve that prevents the engine from creeping into that territory of lean cylinder wall damage. I guess this is also why environmentalists don't like 2 strokes, since perfect stoichiometric balance is too close to the threshold of engine damage.
Spot on!! I agree with everything you mentioned here!
😮e🎉
You probably are unaware, that Every piston is cooling (regulating the temperature) with the "vaporisation heat" from the Extra fuel on Top Rpm. So, with that added fuel, you actually Cool the piston, so, that it does Not Overheat and later start even to seize into the cylinder walls , consequently damaging them. And, because of that extra fuel added at max Rpm, the environmentalists don't like the 2 strokers, beside the added oil in the fuel 4 the lubrication.
KTM has been working to keep their 2 stroke bikes compliant in Europe and has gone to fuel injection. Just isn't possible to have a mechanical carb with one setting be able to burn efficiently across so many variables.
For small engines though carbs are cheap, easy, and reliable. Maybe someday we will have some sort of hydrogen burning engine but by then who knows if there will be supercapacitors that run motors with 10x more power than we get out of engines.
Just found your channel and subscribed, you do a great job of explaining how all this stuff works, thanks alot for all you help.
Thank you and welcome :)
Actually this brother is the first one i have heard so far, about how to properly explain the proper tuning of these membranic carburetored engines. Thanks to brother Tom.
Would also recommend Tom's 'how to tune a chainsaw' video from July 2021 which follows this procedure, but without the tachometer and with no technical jargon. For me, it is the best tuning video on YT, by a country mile.
Thanks again Tim mate :) much appreciated!
Sure : ruclips.net/video/83NF1q0UYPw/видео.html
Great video and good explanation of the goals behind setting the butterflies.
Thank you, glad it helped :)
I have never worked on small 2 stroke engines but I have rebuilt more than my share of automotive engine carburetors and I enjoyed watching. These carburetors are much simpler than an automotive carburetor.
Thanks for watching :)
Exceptional video mate. Really good work
Thank you :) I’m glad you enjoyed it!!
Mate that 011 is bloody gorgeous!! Currently rebuilding an 009L and 011AVT myself😊
Awesome mate!! Happy rebuilding :)
Top quality in depth video.
Keep up the great work
Thank you :)
really simple to follow.. been struggling for some time.. Thank you.
Glad this helped you :)
Great video, thanks for all your efforts to help out the general public.
You’re welcome! Thanks for the kind words :)
Precise, clear and to the point. Thank you, very helpful.
You’re welcome :)
This is just the video I needed, I have a 2 stroke Husqvarna 128ld string trimmer and have replaced it with three, "NEW" different carburetors with the same results. On a cold start it starts perfect, but at half choke it idles very, very high which is NOT normal. After I take it off choke it idles normal, it rev's up perfect, the idle mixture screws are set perfect but when the engine worms up and I pull the trigger, then release the trigger it idles between 3700 and 4000 rpm's. The idle speed for this model trimmer is between 2300 and 3200 rpm's, and 3700/4000rpm's is to high with the trimmer head NOT spinning. Now, if I let it set and idle at 3700 rpm's for maybe a minute or two the rpm's will start to drop then it will shut off. In other words, I can't get it to idle at the normal idle speed without it keep shutting off.
Parts Replaced:
Fuel lines and fuel filter
New Spark Plug
Three NEW, different carburetors and gasket
Also a new air filter
Intake and gasket
My question, would a ignition coil cause these symptoms or what would you suggest I try next?
It doesn’t really sound like an ignition issue to me! I’d check the piston skirt through the exhaust port to make sure it’s not scored. Then do a pressure and vacuum test :)
@@VintageEngineRepairs Ok thanks for the advice....
What a great in-depth explanation and attitude. I don't normally sub to people doing random videos ill only need help with for a moment. You are an exception. And to me that is saying something
That’s really awesome, thank you! I hope
you enjoy the future videos I bring out as much :)
Thanks John!!
Thank you, I've been doing it this way for many years bit this spelled out exactly why and actual steps that I never really thought through...thanks again
Pleased it made sense to you :) 👍🏻👍🏻
A bit overwhelming at first but after a few replays, I was able to get the whole idea. Thank you very much !!
That’s awesome glad you got it :)
Good clear concise explanation! Well done! Thanks Ken
Thank you!
Very informative and clear instructions! Keep up the great content!
Cheers 🤘
Thanks mate :)
Even though I don't own a Stihl, I watched this twice to better understand. This makes a lot of sense now that I understand basics. At some point a similar video for Husky would be more helpful for guys on the other side, ha ha.
Hey! It’s literally identical! It’s the EXACT same process :) I understand it can take a few viewings to get your head around it, but I’m glad it makes sense!
Great video Tom, well done. I guess its easier to explain with a video than over the phone hehe.
Thank you Trains mate :) much appreciated!
Are you the one he says is his mentor
@@JesseNewton-j7mThat’s the one :) you’ll see him pop up every now and then hehe.
EXCELLENT video and very well articulated. Loved it and it helped me tremendously but I am left with one question!
When adjusting the H RPM of the my 455 Rancher, the specs show…
Maximum power speed 9,000 rpm
Max engine/motor 13,300 rpm
Which value am I supposed to adjust it to (less the 500rpm for safety measures)
Hey the second number (13,300) set it to about 12800 and see how you go :)
@@VintageEngineRepairs thank you
Always learning from your channel, thanks Tom. Great content!
Thanks Patrick! :)
Just tried several videos and this is the one that worked on my 201T and 461R. However, even with my H set all the way counterclockwise I still think my max rpm is a tad high. My Tach was one off of amazon and couldnt get a solid read of the high rpms as it jumps quite a bit past 9000rpm but still seemed a bit high. Either way, thank you a ton for this video as it is the only one that took care of 95% of my issues.
Hey :) you’re welcome! If you have the limiter caps on, you may need to remove them to get enough turns on the fuel screws :) hope this helps!
It can be a little confusing, but you did explain it very well, thank you so much
You’re welcome :)
I wish you made all the instructional videos that I would ever need. Very well done.
Thank you! :)
Gosh Dang - a nice running 2 cycle is a dream - great explanation - you really have to be patient with the adjustments - one screw up and you can kiss your shoulder joint goodbye with endless pulls on that nasty jerky little engine - Back in the 70's there were little 2 cycle snowblowers that would never start - of course our 'schools' were worthless to teach us what you just did and so we could never figure stuff out - all that youthful energy just wasted - Now - I ALWAYS run my engine gas out to keep that carb clean - since these little 2 cycles have little tiny ports that varnish up quite easily
Glad you enjoyed the video and found it useful :)
Thanks mate... helped a lot on my Husqvarna 236.
Excellent!!
Great video your explain it is nice always learn alittle more with each video.
Awesome :) glad you enjoyed it!
Fantastic video! Thank you so much for the great explanations!
You’re very welcome! Glad you enjoyed it :)
I love your videos! I’ve worked on my own small engine all my life. I’d like to get a tachometer like yours but the PET2100DXR is so expensive. The 2000DXR is less than $30. Is it as good? I’m 73 and don’t want to spend over $100
Thanks Paul V
Thank you! Is that the one with a red strip around the face of the tach? If so yes, it’s excellent and for all intents and purposes, it will do everything this one will :)
Wonderful explanation. Thank you.
You’re welcome :)
Fantastic video! Thank you for sharing
You’re welcome :)
Hey Tom!
I keep coming back to these videos to help take my two stroke work to the next level.
I have a couple of specific questions about tuning that I can't find the answer for anywhere and I'd love your help.
1. How does an ignition coil with a RPM limiting circuit affect the tuning of the high speed screw?
2. I work on a lot of carburettors (Walbro RWJ-5) with a partitioned Venturi, where the top half pulls in air only and the bottom half pulls a rich fuel air mixture. Are there any special considerations to make when tuning this type of carb?
Hey :) tuning a limited saw with an ignition limiter can be tricky as it can make you think (incorrectly) that it’s still too rich (they sound similar) and therefore lean the h screw out too far. Have a watch of this video I cover ignition limited coils and tuning them here :) ruclips.net/video/sY14oNCXvrw/видео.htmlsi=Wr5S21OS-OhyCnn3
Re the strato charged engines, no there is no special considerations, though keep in mind they do tend to run a bit leaner / hotter as the incoming charge that chases the previous spent exhaust gasses doesn’t have any fuel and it’s the fuel that does most cooling (far more than fins).
Hope this helps,
@VintageEngineRepairs Very helpful thank you.
I had no idea that fuel helps dissipate heat and even just knowing the term Strato charged engine helped me find some other useful videos too. I'll check out that video you mentioned about tuning with limiters now too.
Thank you very much!
You’re welcome :)
Another great video. Hope you can do one on the Echo.
Thanks Raymond! This process will work for any 2 stroke ope mate :) just transfer this knowledge to that machine!
Thank you very much
Can anyone with official Stihl service manuals confirm if this procedure is still current? Mainly curious if this exact method applies to their 4 mix equipment? Or are their slight differences in their procedure and RPM's now? Well done and thorough video!
Thanks :)
@@VintageEngineRepairs so do you know if this same 500 rpm drop tuning procedure is applicable to Stihl 4 mix equipment?
Yes :) that’s correct!
Hi Tom. A good clean description. Thanks. And yes it did help.
In the absence of anything else, do you use this procedure for other manufactures 2 stroke engines?
Absolutely :) every 2 stroke I work on gets this same principle :)
Thanks so much for the video!
How does this RPM meter work and where can I get one?
It seems I can’t tune without knowing the RPM
Hey, you’re welcome :) it inductive! See the description in this video for links to tachs :)
Here in the uk we seem to have some variability in the fuels depending on where you buy from. This variation seems to mean that you can get the tools adjusted right, get another mix of fuel and the tools are difficult to start or die at tickover or tricky to rev up. Have any others found this variation or do most use premium 'proper' petrol (gasoline)? Thanks for some great informative videos.
Yes, I have heard of that before, I’m not surprised to hear it. I’ll often spend 20-30 seconds tuning my machines each time I take them out, though I’m very picky and want them running optimally!
Thanks for sharing, good stuff
You’re welcome :)
I tune by ear free spinning and then tweak it under load, and it always ends up being a little rich without load. That's my target. People talk about altitude and temp quite a bit, but it's going to be a rare case where they take it out of the climate they bought it in. Nobody goes on a world tour and buys a chainsaw as a souvenir. 🤣
Most people here cut their firewood when its 70-90 degrees out but when winter hits and its 0 degrees out and they need a few logs cut they expect it to run exactly like it did in the warm weather and it won't.
Bill a trimmer I can see as you wont use it in the winter but Tom used a chainsaw as an example. Also I use a handheld leaf blower to blow snow off the cars in the winter and I have to tweak the mixture a little when the seasons change.
@@KensSmallEngineRepair Agree there Kenny.
You did a Stihl trimmer carburetor adjustment video awhile back, if I'm not mistaking. If you did, can you share that link with me, there was one part in the trimmer video that you didn't cover in this one. I just bought a "NEW" carburetor for my trimmer, and need the other video to make one final adjustment, if it's not defective, before returning it for a replacement.
Hey :) what timing! I have a strimmer carb tuning video coming out shortly!! I have done one in the past, but no where near as good as this will be. Have a look back through my videos and you’ll find it :) I say hold off as the other will be released fairly soon!
@@VintageEngineRepairsHusqvarna 128ld (manufacture Idle Specs 2300-3200 rpms):
This is a "New" carburetor I purchased for my trimmer and after I installed it, it was idled way to high above 4200rpm's. So I try to keep my trimmer idle speed between 2800 and 3200 rpm's, so when I adjusted the idle screw to bring it down to my idle specs it keeps shutting down and I don't want to have to continue idling it every time I use it. So do you think I should continue playing around with the idle L screw and idle screw or just return it for a replacement. Which I don't want to ship it back because I need my trimmer......
It's a shame that Honda don't tell you since they preset it at the factory which is why I reused the original carburettor when I fitted the Chinese clone Honda GX35 engine onto my dads Honda UMK435 brush cutter attachment.
I am sure that I had the carburettor adjusted to its"sweet spot" using the low speed mixture adjustment screw but it kept stalling after I let the throttle off from wide open throttle & it wouldn't idle during a cold start.
You told me that it could be because the high speed screw needs to be turned in a bit but I still need to check things such as the metering valve lever to see if it's set to the correct height & also that the 1 way check valve underneath the lever for the needle in the metering chamber is closing off when air or carby cleaner is applied to it from underneath the metering chamber.
If I need to adjust the high speed screw then I will need to remove the brass sealing plug on the side of the carburettor which is covering the high speed mixture adjustment screw..
I have refitted the original OEM Honda GX35 carburettor for that reason, even when I was able to restart the engine again when it was warm after it stalled it wouldn't idle until I adjusted the low speed mixture screw again.
That's why I thought that the check valve inside of the carburettor was sucking air into the metering chamber through that check valve which may not be closing off !
Best of luck with it :)
Excellent Presentation - thanks
Thanks for watching :)
I use an old Bike shifter lever with cable to control the choke since I live in Northern Ohio where we can have 30 ish F and 90ish F - so I find controlling the choke is nice but not possible with a Back pack blower - so with a Choke control near my hand I can adjust the carb knowing that I can adjust adjust the choke if (in Autumn) we went from 73 degrees Monday to 39 degrees Tuesday -
Very interesting! It’s not an ideal way to do it, best you just tweak the carb with a screw driver and let it breath in the correct amount to get a full cylinder charge :) I will tune my equipment multiple times a day depending on changes in temp or altitude. It’s not really necessary for most people, but I like my engines to run where they are best.
@@VintageEngineRepairs I went on your channel and then saw all the 2 cycle stuff - had I known that I would have kept my caveman method on the down low - For me it's a practical solution and I can just edge that choke controller an itsy bitsy bit to get that blower into some high sonic rev's - but what would be nice as per your advice to properly adjust the needles or to have a servo controlled needle adjuster with an RPM device - oh and also a 'cordless drill' type starter motor for the backpack blowers would be good - thanx for the replys
@TotalFreedomTTT-pk9st haha no not at all, we all do what we want, it just wouldn’t feel right if I didn’t mention a quick tweak is normal and you’re not the only one so don’t feel like you’re doing anything wrong :)
Just the information I needed. thanks,
You’re welcome!
Great info Tom mate
Thanks Conk! Great to hear from you mate.
Brilliant mate........thanks for being so clear and concise. My engine tach has a wire that you wrap around the plug lead. I changed it to a crocodile clip for ease of use. I'm just wondering if this type are as accurate as the ones like yours? Cheers bruv!!
Thanks mate :) yep! Mine does both inductive and wired! Some cheaper brands aren’t as great, but most are still very accurate!
@@VintageEngineRepairs Okay......so do you think adding a crocodile clip to the wire may have affected accuracy? I just thought that winding the wire around a lead was a faff......much easier to clip it on!!
I haven’t found it to make any difference because this tach has excellent inductive pickup, however the cheaper ones do benefit from that!
@@VintageEngineRepairsCould you provide a link to the tachometer you used please & thanks!
@@danielbrown9469 sure :) Engine Tachometer - amzn.to/3TE48GZ
Appreciate your guidance and will try again maybe I’m turning to fast. I don’t have a rpm gauge, did you have a link? The LA screw, didn’t seem to do anything do you screw that in all the way and then out 1 1/4 turns also? How do you know where it should start from or doesn’t it matter? When I quit it wouldn’t stay running also I have replaced the carb.
Set that so it just touches the cam to open the butterfly and then one and 1/4 more :) here is the link to a tach :) amzn.to/3TE48GZ
Very helpful and clear thanks👍👍😎
You’re welcome! Glad you enjoyed it :)
Thank you. Very good instruction.
Thank you!
Great info Tom on a very popular issue! Speaking of Stihl tachometers, mine seams to be acting up. Is there a hack to replace the battery? 😁 I never thought I would have to deal with this! 😭
Hey mate I don’t have the stihl version, but no they’re not replaceable!
@@VintageEngineRepairs bummer thanks though Mate!
Dude, I appreciate the 101 but can you give us a close-up shot of where exactly on the spot you access the car?
Hey, see my most recent video, it’s much more detailed :)
Well done Thanks. My saws thank you.
You and your saw are welcome 🤣
I have a Stihl KM-56 Trimmer. It has spark, new tune-up kit and carburetor. All fuel lines and tank vent line were tested. Muffler and spark arrestor screen clear and clean. Compression test and pressure test all passed. Stihl won't start! I'm confused! What could be a possible issue? Thanks and I have learned so much from your great videos!!
Hey :) I’d recommend putting a teaspoon full of gas and 2 stroke mix directly into the throat of the carburettor. Then make sure choke is off, ignition on, go full throttle, and pull the cord a number of times. Let me know if it starts, runs then stops after a few seconds :)
@@VintageEngineRepairs I will try that at work tomorrow- Will let you know. Thank you! :)
@ninagamble9150 no worries :)
Great video Tom! I understand the process to get L & H screws set, but unless I missed it, I don't recall you saying anything about dialing idle back to spec rpm. Sorry if this is obvious, but should idle be left at spec + 500 after H screw is set, or does it then get reset to spec rpm with idle screw?
Hey :) I covered it haha, when you find fastest rpm on L and it stays at spec + 500, then richen it by 500rpm with L. Thanks for watching and commenting :)
@@VintageEngineRepairs- my apologies for not following close enough - thanks for the lightning fast reply!
Thank you for your brilliant video can you set the butterfly on carburettor between the idle port and first progression hole by eye with carb of and tune low speed screw and achieve same result ?
Thanks :) na you can’t, even 1/8 of a turn is a lot on the LA and you can hardly visualise that. There is quite a range between the idle drilling and progressive.
Thank you for your reply I'm probably nearly 40 years working on small engines here in Ireland you learn something new everyday 👍
@@patrickkelly7674 you’re welcome! Yes you’re quite right!
♥️
One small issue with the recent models is the speed limiter in some of them. To the novices when the limiter kicks in they might think the engine is four stroking and keep leaning out the H.
Yes :) spot on! Check out my most recent video 👍🏻
@@VintageEngineRepairs I am a self taught repairer and what you say here is what I do by instinct . Sharing it with several younger guys here in India. Thank you
Nice video Tom. Does this procedure apply to 4-mix engines as well or is it different for them?
Hey Richard, this is only 2 stroke engines rather than Stihl’s 4 mix. Thanks for watching :)
Thanks. Good explanation
You’re welcome 👍
This is a good video but I have one problem with their recommendation. Lets say desired speed is 10,000 and the tach shows 9,000 because they already have it so lean it won't reach 10K. Now they turn the screw in to lean it out and raise rpm but don't get the desired results. At least with the low speed you find the sweet spot and adjust from there. I don't like recommendations that just have you read a tach because the magic number your looking for occurrs twice-once on the lean side of the hump and once on the rich side. Does this make sense?
Hey Scott! I must admit I have never had a 2 stroke that I couldn’t reach their max rpm on the H screw? Maybe I’m miss understanding your comment?
There are a few changes I personally make to their lean drop off tuning procedure, but for continuity of the process I didn’t add in any of my own preferences on this vid 😂
Edit:
Ahhh I think I understand you!! Yes, if you go too lean you’ll eventually hit that number again. I haven’t tried it, but I don’t imagine that on the lean side, it will hold the set rpm. It will lean out and die? Maybe I should give it a go!!
@@VintageEngineRepairs Yes you got it. The point I'm making is that if an average guy just throws a tach on it and turns screws till he sees the right number, he hasn't necessarilly set it correctly. I've had saws come in where guys have done exactly that.
Scott, I adjust the high speed screw to just get 4 stroking out of the wood, so it cleans up in the cut. If the tach shows its off (too high) i may richen it a little, but I adjust to ensure good pulling in the wood.
@@TheGreasyShopRag it never ceases to amaze me what people are able to achieve 😂 it hurts my head LOL I’m sure you’ve seen some real doozies!!
@@KensSmallEngineRepair Yes thats the way I do it and rarely is it set too fast. I prefer being slightly rich over slightly lean.
Not much use when the engine won't start. I'll save this one in the event I can get to the warm up stage.
No worries :)
As far as it goes, your video is good, and very helpful - but as I said, as far as it goes. I say this, because I have a Stihl FS 120 Bushcutter (circa 2002 manufacture), which ONLY has 1 adjusting screw - the Lo + and -. Even Stihl support was unable to give me a part number for it. Does anyone out there have any ideas which carb it might be ???
www.amazon.com.au/gp/aw/d/B07D2XWZWG?psc=1&ref=ppx_pop_mob_b_asin_title
Would you reccomend doing this without a tachometer? just by 'feel'? Cant afford the £150 for a tach right now. Many thanks for the informative and easy to follow video btw.
Hey, yes, I go by ear most of the time and just confirm with a tach, but I only recommend it if you know what you’re listening for. Otherwise you’ll likely cause yourself problems!
Hang on now... there is no way you can do this stihl method without measuring rpms. No one can know what 3000 rpms sound like. It's the target point... you can't know if you are too high or too low without a tach
@@PopaAlexandru. nice! Yep you can get cheap and expensive Oppama tachs!
@@normanbfifteen3468 by ear, when you know how, is far more accurate than shooting for numbers, every engine is different, even if it’s the same model, numbers are an accpectable range to be in. Using your ears you can tell exactly how the engine is running and where it’s happy. The spec rpm’s are a rough guide acrosss the board, for a brand new, non broken in engine with good soft diaphragms, clean filters, sharp chain etc and will be fine, but as an engine wears in, filters may be a bit blocked, the chains not quite as sharp etc, being able to adjust an engine based on how it sounds is really the best method. Also, I can be almost if not, spot on by sound. Just like you know when your car is at 2,000 rpm, 3,000 rpm etc, you build up an audible “picture”. Just like you know when to change gears, you don’t look at the rev counter; you KNOW when the engine wants to change. It’s a similar principle here with these engines.
@@PopaAlexandru. Sure, if you have perfect pitch... ha ha. Even most pro musicians need a reference point to compare when tuning an instrument.
Great explanation!
Thanks :)
Great video , now I only have one question , where can I buy one of those Tacho's you are using ? How does it work ?
I’d recommend a fast tach, but cheaper, works just fine. This one is unnecessarily expensive
@VintageEngineRepairs I just started scrolling ebay and found one for 40 bucks so thought bugger it I might as well get it . I have 4 carbs to replace on some old equipment of mine so it will see some use . Great video btw , 👌
Great video!
I have one question though, does the same procedure apply to a 4-MIX engine like on the FS130?
I can’t be certain I’m afraid!
Can you tell me how to set up the tacho in your video. I’m struggling with the enclosed instructions. Many thanks. Good video
Sure, what tach are you using? I only have two, both you just put near the engine and they fire right up.
It’s the PET-2000DXR. If I press the mode it shows 0 min. If I press and hold mode it shows 7760 rpm. Should I see P21:42 ? Many thanks
@@grahamjones4294 yes you want 21:42. Keep pressing the mode button until you get to the screen that starts with a capitol letter “P” followed by numbers. When you get to that screen, press the set button until you get 21:42. Then you can just leave it alone. Bring it next to an engine and it will register both 2 and 4 stroke engines that fire every revolution (all single cylinder ope)
Sorry to be a total idiot but do I hold the mode button down or continually click it. I either get 0mins if I click or 7760rpm if I hold the button down.
@grahamjones4294 keep clicking it to cycle through the settingd
Does your tachometer work purely on sound with no leads to spark plug cable etc?
I’ve been struggling to find one of these got a link for one?
Hey mate yes it’s inductive :) here is a similar one to what I use, just way cheaper. The only
difference is this one doesn’t do quite as many cylinders - totally unnecessary for any ope! Save your money! Engine Tachometer - amzn.to/3TE48GZ just for full transparency this is an Amazon affiliate link - I may earn a small amount from qualifying purchases :)
Nice one dude/s and many thanks.
You’re welcome!
Interesting! However, I cannot find this info in any Stihl publication or manual?
You’re not looking in the right places haha :)
You do have any idea what is wrong in my fs38. I put brand new gaskets in carb and changed spark plug. It hardly runs idle when L and H are closed. Immediately when i open L it will stall. If i pump on top of the carb it keeps running.
Hmm pumping on the carb keeping it running indicates a fuel supply issue. I’d double check your work, pressure test the fuel lines, filter, tank vent and carburetor. Check your don’t have any air leaks in the mounting area between the carb and the engine either
@Tom
I think your video was good but needed to be watched several times. Your chapter settings really help.
I got confused by your different terms and the way you changed between them when you speak. Though you can get it from the video, you use a lot of terms interchangeably without realising it because you are experienced.
It may be better to give a list of the different terms at the outset and then just use one term in the description of what you are doing in terms of names for the screws, speeds and alteration of the screws (clockwise[right,turn it in, lean it out], anticlockwise). Meant to be constructive as your video is good, but could just be a bit easier for certainly me to understand if you used less terms and maybe set out the alternative terms at the start
Hey! Thanks so much for the great feedback. I couldn’t agree more and you won’t see a recent video of mine like this one. Now days I plan all my tutorial videos out in a scrip so nothing gets missed or miss communicated! Thanks again :)
Where do I get a handheld Rpm gauge? How much does it cost?
Hey, there are links in the description for you :)
Where you get that tach? Everyone ive bought has to wind around plug wire,. Thanks for videos
I brought it online, it’s called an Oppama!
That was Excellent! 🙂
Thank you!
Great Video. I have a SH55 blower and I see the idle rpm is 2800, but there is no max rpm in the manual or online for that matter. Would you know what the max rpm should be? Thanks for sharing.
Interestingly enough, they don’t give a max rpm, not sure why. Set it to max rpm, then back it off 1/8 of a turn.,
Thanks very much, have a great day.
I just got around to adjusting the carb and no matter what I did I couldn't adjust it properly. Could be because its a Chinese carb. I have ordered another carb, let see what happens.@@robsteinhaur221
clear as mud
🤣
Can you add a link to the tachometer you are using please
Although I don’t have a link, it’s an Oppama 2100DXR
Does this also apply to the Stihl 4-mix carb?
Yes it does :),
What is the make & model number of that tachometer please
Hey! Sure, google “stihl edt 9” and it will come up :)
Question. Is there a cheaper tach on the market that will work?
@@user-lp3cf5yn5b sure, grab a fast tach 👍
Here's one for ya, my kid was playing with the idle screw and screwed it all the way in , not while running though, how do I find the idle setting again , it must have been turned in 5-6 times. Would I turn in all the way, then turn back all the way , then turn in half way ???
Na the best thing is to turn the idle screw in until the chain just starts to move, then turn it back until it just stops. That’s a great place to be.
@@VintageEngineRepairs ok the idle screw is turned all the way in until it stoped, so your say. Back off the screw 5-6 turns and then start turning in
Stihl 461
@@200cdl huh? No I didn’t say that at all lol. Re read my comment above lol
Kid was playing around and kept turning it in all the way until it stopped turning
On my STIHL BG 56C Air Blower, I have a problem starting it. I have to push the carburetor bubble about 50 to 100 times before it will get gas inside the bubble then it will start. I have replaced just about everything and no luck on starting it normally.
What should I do ?
Likely either the celerator pump, main nozzle check valve or if the carb has a part load fixed jet check valve that maybe leaking too.
got it. Thanks again
Awesome Bruce :)
Stihl 025
Let's see if I get this proper
New and proper fuel mix and full.
Fuel filter not blocked.
Air filter clean.
Exhaust clean.
Spark arrester clean.
Spark plug and gap proper.
Oil resivuor full.
Chain proper tension.
Sharp.
Before factory reset:
Turn the H & L to seet in the "IN" position (clockwise till it won't go any further-gentle).
Factory reset:
Then turn the H & L "OUT" (counter clockwise) one turn.
Start it.
Let it warm up one minute at different rpms.
What is the factory reset for the LA screw?
Good job, there isn’t a factory preliminary setting for the LA :)
I set every two stroke carb to 1.5 turns out on both jets. This should get the piece of equipment running and I tune it from there. I warm them up for five minutes before adjusting the jets.
Worth noting, the engine will be just as hot at 60 seconds as it will be at 5 mins UNLESS you’re actually putting the engine under load. If you’re just letting it idle and gently blipping the throttle a few times every so often for 5 mins you’re wasting your time. It’s not until you are actually using the engine under load that it’s going to get hotter. Air cooled engines heat very quickly.
@@VintageEngineRepairs that is what the Husqvarna Service Manual says. I do not know what the Stihl Service Manual say, so I go along with what Husqvarna said. I looked over the Instruction
Manual for the 021, yesterday, and Stihl does not provide an RPM for idle or Max rpm, so I will go along with what I know. I figure 2,700 and 13,000. What do you think. A lot of their saws list 13,500 for max rpm, but I never figure that high. I had a brand new MS 170 that was turning 14,500 but not any more. I richened it up to 13,000 and change. They say you cannot adjust the H on theses saws, horse crap h- you can. There is a very small torx socket in the H jet. I just richened mine up a 1/4 turn, down to 13,020. I could have turned it out a bit more but left it where it was. 13,020 is not alarmingly fast to me.
All good, we all have our ways of doing things. The 021 is 2,800 / 11,500. Thanks.
@@VintageEngineRepairs I haven’t thrown the tach on the 021, yet, but will keep those figures in mind. It’s has new bearings, seals, piston and cylinder on it. I wait until things get broken in before
I set the carb. It has a nice little four stroke on it, now, so it is ok. 11,500 is kind of low for a Stihl. My 260P will turn 13,500 easy. I am not worried about it turning to high an rpm with a 18” .325 chain on it. What I like about it is it’s easy of starting - 2,1P every time. Three pulls and your going is great for a Stihl saw. I can’t wait to see how it acts in real cold weather.
Where does one find the tachometer?
Hey, I put a link in the description to the tech and other tools I use in this video :)
Found you looking for a solution to a chain saw problem. I have a Stihl 032 AV that I have owned since new. The trouble I’m having is that it will start and idle fine but bogs down and stalls when I pull the trigger. Fuel is new and I don’t see any obvious holes in the fuel line or pulse line, fuel filter is new. There isn’t a spark arrester just a muffler. The only work I have ever done on this saw is a carburetor rebuild kit a couple of years ago. The saw was running strong up to a few weeks ago. Any thoughts?
Hey, could be many things, but essentially it’s lean on the progressive idle drillings. Try opening the low screw 1/4 of a turn (you may have to turn the idle screw in to compensate and bring the revs up).
@@VintageEngineRepairs thanks, I’ll give that a try.
@@VintageEngineRepairs that worked well! It now runs and cuts but still has some power issue. I can tell it isn’t putting out all the horsepower it used to and will stall now in hardwood like walnut.
@@54lespaul77 in that case, if it’s stalling at full rpm, open the H screw 1/4 of a turn
It seems as if Stihl's aim is to set the butterfly open as far back as possible at the first progressive drilling, with plenty of fuel flowing out of the 3 idle drillings.... So that when you hit the throttle the butterfly is already well opened and has little distance to travel to WOT. Add the fuel from the 3 rich low jets as well as the high jet and it is no wonder it picks up instantaneously. It is like a gun that has the trigger cocked -vs- having to cock the trigger before firing.
Hey :) fuel flows through only the idle drilling at idle - air actually flows into the progressive idle drillings from the high pressure choke side and form an emulsion with the fuel. It’s not until the butterfly is progressively opened that fuel flows out of the progressive idle drillings.
Yes, that makes sense. It is hard to picture it, but that is a good description of what is going on. Thanks.@VintageEngineRepairs
I have a question. A lot of Stihl equipment has an idle range like 2,800-3,200. Which number do you choose? 2,800 or 3,200?
Hey! It’s engine dependant; as mentioned in the video. Your service manual will state what rpm it should idle at. Thanks for watching!
What I worry about using break fluid to soften rubber is how long will it stay soft once exposed to gas. Nags has a tendency to harden rubber and I think it will get hard, again, in short order. This is why I replace diaphragms instead of trying to rejuvenate them. I do not like to have to go back in a carb, again, for the same reason. A fools errand.
Very interesting indeed...
Thanks 👍
a stihl bg50 has limiter caps, where does stihl have the oem settings at before the caps are installed? or do they have a spec where the L and H screw are installed before adjustments starts before the limiters are pushed on, I do not have a service manual to look this up, thank you
I’m not sure I’m afraid! Do a quick google search :)
Where did you get that tach. The one from Stihl is close to $100
Hey :) this is more expensive than stihls tach, this one is about $350 Australian dollars. It’s called a pet2100DXR. I have heard the tiny tach or fast tach are quite good and are cheaper :)
Do this for sthil 220 i dont have device for checking rpm
Video will drop soon on tuning a weed eater by ear.
So you’re saying this is standard for BR400 also? Mine won’t react to idle screw. And I don’t have a meter to use. What to do?
Yep, it’s the same process :)
How should or what is the factory setting for the idle screw?
I looked up BR400 manual and it does not say what the L&H are set in the factory, maybe what you know is as a Stihl Tech you have access to the info.
Can you tell me where to start?
Hey, just to confirm, I’m not a stihl tech! I don’t want any misunderstanding there :) start at 1&1/4 turns out on both L and H and start from there. Use 2800 as your idle. So…
1). 1&1/4 on both screws
2). Start machine
3). Let it warm up for 60 seconds (adjust La if it won’t idle)
4). Adjust LA screw to 3,300
5). Turn L in and out to find fastest rpm
If fastest rpm isn’t 3300 (+/- 200rpm) adjust LA screw to 3300.
6). Turn L in and out to find fastest rpm again, it should be at 3300rpm (+/- 200rpm) if not repeat adjusting LA to 3300.
7). Turn L screw anti clockwise to set rpm to 2,800.
8). Go to full throttle and turn H until you get fastest rpm.
9). Open H screw 1/8 of a turn anti clockwise to richen the mixture.
Tuning complete!
@@VintageEngineRepairs😢 0:33 0:33 0:33
Explain stihl fs55. Max.engine speed (rated) 9500rpm.
Max.output shaft speed (cutting attachment) 7700rpm .which one of these rpm the H speed is to set
When the machine isn’t under load it should be set to run around 9500. However because you’ll be cutting grass, the engine will be loaded because of the resistance of the grass so it won’t ever run at 9500, it will be at around the 7500 rpm in use. Tune to 9.5k if that’s what the manual says max rpm.
Thanks very much
What is the minimum compression a stihl FS55 trimmer should have to operate?
About 130 psi, below that it may struggle to start. You must use a small engine compression gauge though, an automotive one won’t be suitable.
Thank you so much.
You’re welcome!