surging problem with B & S engine on Craftsman riding mower
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- Опубликовано: 15 сен 2024
- this has been a pain, it doesn't want to come down to idle and sit there, it seems like a passage in blocked in the low speed side of the carb but I think surely out of 3 carburetors there would be some difference.
My Craftsman lawn tractor was doing the same thing. It was a good time to do a preventive maintenance.
I suspected a fuel issue and basically what he did except I did not swap carburetors. But I did remove it and basically cleaned it. I never thought opening the carburetor up but just give it a good bath with brake fluid.
Considering the way it was running after starting the mower, I just knew it was a fuel issue….somewhere between the gas tank and the carburetor.
I read all comments on this thread and ran across 1 comment that I never thought of and made perfectly good sense.
The comment was “the gas cap”.
The next morning I unscrewed the gas cap but left it over the the tank opening.
I turned the starter and “BOOM “ cranked beautifully, it did surge a little bit, but after it ran for a solid hour, it ran and sounded like a new engine.
If you ever suspect fuel issues, don’t forget the gas cap is part of it also.
that fixed it for me
I'm going to go try that now. Lol I'm having the exact same problem
Ty I will check mine !
Late on my response but, someone might find it useful. The surge is because either too much gas or too little. Depending on the carb, you must warm up the engine then slowly screw in our out the jet screw until it runs smooth. Black smoke means too much fuel
What if it runs in nutral fine but in drive it’s surging
@Willysworkshop ...normally she's starving for fuel, so I'd give the carb a good clean
Nikki carbs are notorious for this problem. The jets on the 16+ hp motors are undersized, and need cleaned at least every 2 years. Best to bore them out.
@billyjackson5664 ...I definitely recommend a fine drill set and slowly increase the bore and find that sweet spot
@@andreibaity6152what if it surges on start but when in high it runs good then when I slow the engine down it dies
Hi, I had the same problem on a Craftsman LT 2000. I finally figured out that it I a leak in the Engine Intake Manifold either past the Carburetor or at the Cylinder. I solved the problem with anew gasket and by making sure the bolts are iight
It was the low speed jet. Those are Nikki carburetors. They are only about .015 thousands of an inch from the factory. Because of EPA regulations. There are no adjustments on those particular carburetors. The aftermarkets state they are good for 10 horsepower to 18 horsepower. Once you get close to around 16 horsepower and above they are not efficient no matter what they say. The jet is located inside above the float assembly. It needs drilled out using micro drill bits. The reason they work great when it was new is because the ethanol hasn't had a chance to gum it up yet. Once it gets older it starts to do this surging. Generally drilling it out to about .024 thousands of an inch gets the job done. You really want to try to take it one step at a time. That's about a .6 mm drill bit. Very small. NOT 6MM--- .6MM there are other videos showing where this is located and how to step it
Omg I will never be able to fix mine 😳
make sure the hair thin spring that's wrapped around the throttle rod is there and attached at both ends
I need to know where. Because mine came off. And I can’t find where to connect it to.
@@speed1st On the Walburg carb on my Briggs and Stratton the little spring connects from the governor arm to a hole right next to the linkage on top of the carb. It has a big impact on surging if its not in place. There is a video on here from a guy that found his had broken. Simple fix.
I don't think this would totally be the cause, but your fuel filter appears to be on backwards. There should be an arrow on it to show you the proper flow of fuel through it.
Right, it is backwards. Arrow is hard to spot, but indicates direction of fuel flow.
Most of the Briggs have a dampening spring which runs along the governor linkage to the carburetor. I have seen this come loose and cause just what your engine is doing. It could also be a vacuum leak around the carburetor. Check those and let us know what you find. Hope this helps. Good luck.
If you can slowly close the choke flap and it smooths out, the idle circuit is stopped up and starving for fuel, or you could have a cracked intake manifold.
I have a newer Briggs and Stratton and this is what I did. Replace or clean air filter, remove and spray carb with carb cleaner, and clean everything in between. Get a better quality iridium spark plug. Clean or replace fuel line and replace fuel filter. Small serving of Seafoam DeepCreep into air intake for some lubrication and run that thing wide open for an afternoon. Anytime a small motor is struggling you can bet a paycheck it has something to do with the 3 boom ingredients. Fuel, air, or spark. A quick tune-up should be done before every season.
simpler remedy is to get another model mower. The older the better.
@@caroltenge5147 it's true they don't make em like they used to but a motor is a motor. Keep it clean and give it what it needs to run.
What fixed it for me was replacing the spring that is attached to the governor. The spring is located behind that small plate that the throttle cable is attached to. At the end of the throttle cable you can see the white piece of plastic that slides back and forth as you move the throttle cable. It is on the other side of that plate. About 3 inches above and to the right of the oil filter. My spring was a little mangled and a new one fixed it.
I took the air idle needle out cleaned the orifice with seafoam took some fine sandpaper and cleaned the needle and it helped 80% I'll have to live with the other 20%. I was beginning to believe I was the only one that had that problem until I saw your video. getting closer though.
We just found the issue we had the same issue did everything put a new carburetor and everything.. come to find out it was a bad gasket on the intake . The one that bolts on to the valve cams. It fixed the issue
Sorry, which gasket is this? Is it behind the carb? Or the gasket over the rocker arms at the front of the motor?
take the low speed jet out find a drill bit that fits in it then get one the next size larger and drill it out Problem Solved
I can tell you what I went through. End of season last year Engine got heavy to turn. It has 16HP and one spark plug. I removed plug and air filter. Gas was in both places. Oil level was high.
I knew that the Walbro carb had a needle valve leak. Put on a Chinese carb and could not get it to work properly, also put a gas shut off valve.
I lapped Walbro seat using a drill with wooden cue tip some polish and it worked. I finished the season.
This year 1st cut I lost power and started surging. Well I found that the shut off valve was plugged from stuff in gas tube. So I cleaned the tube and put another shut off (I bought 2). I finished the grass and it was a little erratic running (I had reinstalled the Chinese carb) but was able to finish with no loss of power.
I imagine that dirt from gas tubes affected both carbs. So I will clean bot carbs.
I would diagnose these surging problems as such:
1- Loss of fuel
2- Dirty Carb
3- Intake vacuum leak
4- Bad Ignition coil (intermitent) replace
5- Sheared fly wheel key
yes, this gas now a days that part moonshine is messing up a lot of fuel systems, eating up rubber hoses and plastic parts.
Ignition coils either work or they dont. They dont start going bad they just quit.
Ignition coils or magneto's can have corrosion between them and the flywheel, they can be crusty where they bolt down.
The kill wire can be damaged and ground out. They can need a new end inside the park plug boot.
Don't say it's only good or bad, it depends what test of many it may fail.
Also, they can arc from a damaged high tension lead.
There's many methods to repair little issues they may have.
That's why God made mechanics.
When the problem makes a mechanic dizzy, he needs a technician to help diagnose.
Hope this helps somebody and saves them time and money and gets their grass cut before it gets so high, they have to mow with a weed whacker.
@@billycolwell4263 you are dead Wrong. They can be bad and deliver poor intermittent spark. Had a surging Mcclane edger with new carb, fuel lines, spark plug, the works. Sometimes a spark sometimes none. Changed coil, runs perfect now. It ran erratically for years with that defective coil. Cleaning all the rust off did not make the old coil work right even though it tested out good at 4 ohms. You obviously don’t know what you are talking about saying they either work or they don’t. Lol
@@billycolwell4263 Usually, but if that doesn't happen, it'll drive you crazy. Some coils can also burn out with the wrong plug. For example, Husqvarna two cycles. If you put a non resister plug in it, it'll instantly burn out something electronic in the coil. It's work, but not properly. It's a good idea to use a plug with an "r" in the number. Hurts nothing to have it, so far as I know, and not having it will ruin some coils. I made this mistake more then once with Husqvarna weed eaters, and just had no idea what was wrong.
Check and make sure the intake manifold is tight where it enters the head and you might need to adjust the governor also. Mine had one bolt that wasn't quite tight after 15 years of use.
How do you adjust the Governor ??
Take the fuel shut off soliniod out cut the needle off. Put back in and ur fixt. If u have a gravity flow fuel system witch it looks like put a manual shut off in line. Works great
Where is the spring on that throttle linkage?
Adjust the air fuel mixture run the screw all the way in and take it out 1and a half turns
I have the same problem with my 2000 craftsman rider and all new parts, tank has been cleaned a féw times, new carburetor and ít runs fine then dogs out ít has done that moreless since brand new i could use idea, Thanks
I have the same problem with my Briggs & Stratton put a new carb on still has same problem
My John Deere with the Briggs engine kept doing same thing. I had changed a lot of things then I watched a video that said the electronic round thing on carb bowl was either sticking open or shut, that I could put an inline shutoff valve in the gas line around the filter to full pump but to cut the end of that round thing that controls the gas into the carb. bowl. I did that this morning and my mower started right up and didn't die out but did surg until I adjusted the gas screw and lowered the chokd idle control handle to halfway point. It sat and ran good but a little fast for about 12 mins. so I got on it took it about 50ft. tried to engage the deck, the engine stopped, flooded gas out of bowl and now won't start again. I covered it up and walked away. This mower only as about 245hrs. on it. It is agrevation but I enjoy just tinkering with them. I have a stack of riders that all have some issues and a stack of self and non pullers mostly the kind all 4 wheels pull. My dad was a lincensed mechanic for over 50 years so he taught me a lot about engines and tools.
actually it started running right after a while. I think there was a very small piece of dirt in the main jet at the bottom of the carburetor.
It's the top jet by the throttle adjustment screw on top of carb loosening it runs fine but then vibrates back closed and starts surging again
thank you.
It's simple-minded the same thing and I did valve adjustment and it runs nice and smooth now
Tried that it did help with the starting but did not help with surging.
I am going to try replacing the fuel lines because ethanol turns rubber to crap and installing a new fuel filter.
I fixed my mower today with the same problem as this one, whoever owned it before took it to the special shop and they couldn’t fix it and the problem is easer then we think all you need to do it level up the fuel filter and level it with the carburetor and that’ll fix you’re problem 🇲🇽🇲🇽🇲🇽🇲🇽🇲🇽🇲🇽🇲🇽🇲🇽🇲🇽🇲🇽🇲🇽🇲🇽🇲🇽🇲🇽🇲🇽🇲🇽
Are you serious ? It looks like it could be anything 😂
I had that happen to mine a few years ago and it turned out to be the spring that goes over the throttle rod was broken on the end. Bent a new hook on the end and it stopped the surging.
Mine was the spring on the automatic choke. Wasn't opening as it should. Replaced spring, problem solved.
Is there a spring missing that the governer rod runs through? The rod that runs from the governor arm to the carburator. A spring usually runs along side it or around the rod and is attached to the governor arm and to the same point on the carburator the rod is attached to. It keeps the slack out of the hole the rod attaches to. That little bit will cause surging.
Sometimes the fuel shut off solenoid goes bad or you don't have electricity to it. (That's the part sticking out of the bottom of the fuel bowl.) It is supposed to close when the key is off to stop backfiring caused by the more volatile ethanol gas. When the key is on, it opens up allowing full flow. There is a spring I think that is activated by the solenoid which moves a stem in the center of it. This is what does the plugging. If the solenoid goes bad, or if there is no electricity to it, then this center stem can slide up and down, blocking and then clearing the main jet. I just cut the plug part off with a dremel. It worked fine after that. Of course, if you live in an area where they check emissions, you'd better not do that.
thanks for the info,
That's some good advice, on some Kohler engines, the plunger just slides out of the control valve. I did that to mine yesterday and it works fine. I just got this thing, it would start and run for a few seconds then die, removed the plunger, now it runs great. Some of the Briggs carburetors you need to cut the plunger off, either way it works. Have a wonderful day sir 😊
How without leaking gas I have that problem but have push button to start
@@comingasathiefinthenight1120
Having a push buttons isn't a problem, someone just got tired of chasing wiring problems and by passed the problems. I have done that to. You could put a fuel shut off valve in the fuel line if you are having problems with it flooding the engine, just shut the fuel off and let it run out of gas, it can make it a little hard to restart the next time you need to use it . If the float is working, it shouldn't flood the engine. Just a few suggestions in case you need some ideas
It's the governor, found this video while searching for a adjustment guide
BTW Thanks!!! I hadn't eliminated fuel system errors, went straight for the governor, this video just saved me a lot of tinkering 👍
Turns out it was indeed the fuel delivery. Was using a very old filter, after messing around with it (and cleaning the carb) it "broke down" and a bunch of debris when into the carb. After a second cleaning it ran smooth
I was thinking the spring may be stretched & needs to be shortened. I see this was over a year ago, what finally stopped the surging?
Just took mine to the shop for similar issue but with backfiring. Good luck.
What did it end up being?
Mine is doing exactly this, and I just put a new carb on it
@@splash5974 backfiring 'most of the time' is the retainer pin on the flywheel shaft has sheered and you need to pull the flywheel and put a new pin. The magnet pad on the flywheel passes the coil as it spins and sends the spark. When the flywheel is twisted off center because of the broken key pin, the timing is moved and it is firing at the wrong time. When it is NOT the flywheel.. you are likely screwed. Replace the coil. Make sure you do not have weak intermittent spark. Some engines have an anti-backfire feature built into the air cleaner cover. If you have that.. it can get broken wires or otherwise malfunction.
@@gravewalkers I set the valves and put a new carb on it, and it runs great!
Bud, it's the carb. Both might of those you had probably was clogged up at the float cutoff. Have you had a real dry season? Cllogs them right up with the dust.
Now you got us hooked and you need to finish this fix to keep your man card!!... Lol... Good luck my friend!!.. You have some expert advice here in the comments Brother!!!!
I might just leave it as is, when I am cutting grass, it smooths out and does fine,
Looks as if your throttle rod spring is missing. It is a small skinny spring the spring end is at the throttle and the long end goes on the hole on the carburetor .
Hello There is a low speed orfice inside carb once you remove bowl. It sits down in the valley of carb. It’s probably dirty and hole shrunk in size diminishing flow. It’s brass. Clean it with a small piece of wire or tiny drill. I’m sure there’s one on the original carb.
Probably not on 3 different carbs it didn’t...
Use Stabil in your gas to avoid this issue. It cleared up the surging with one mowing.
On a different engine i had that problem and it was on top the new aftermarket carburetor the plastic piece for the throttle linkage was rubbing against the carburetor and not freely moving how it should so i took it back off and moved the piece side to side to loosen it up like the old one was and now on start up it sounds a little funny then runs smooth after a few seconds after start up that was my problem you was having with that engine you got mine works fine now no more surging.
You could still be missing something inside the carburetor.
I still have a continuing problem with the old Kohler command and Kohler pro and cv16s cv15s cv491s engines carburetor bowl floats while on a hill or coming to a hill to go up it or stopping on a hill their shitty floats wanna close and cut the gas off everyone else wants to think its the gas and its not the gas its something wrong with Kohler carburetor bowl floats on brand new Kohler carburetors for those models they have the problem when a gas pump is hooked up and or if its gravity fed the problem is the float and there's nothing to adjust far as i can see
The 2 cylinder Kohler 20hp doesn't have the carburetor bowl float problem i wonder why neither does the 22 i wonder if either of these 2 carburetor would fit onto any of those 3
Someone gave me a 6 hp Briggs and the engine surged, I realized the governor spring was in the wrong hole and now it runs good.
Get a set of tiny drill bits and open up that low speed jet a little.
I have a surging problem on my B&S riding mower. Mine then dies. I’ve just seen a video where the guy found a break in his fuel pump hoses. Fixed them and his problem was solved! That’s where I’m headin. Pray for me.
that might be it,, actually this one sort of fixed it's self, I started mowing and it took off and ran right,must have been some dirt somewhere, I have since sold the mower.
I started at the carb intake at the block ,and changed that piece out, Motor started and no more surging and it runs great
Valves needs to be adjustments in it will quite I work on them all the. Time
The fuel filter is on backwards I believe. Does it surge with the air cleaner on? Correct spark plug? And make sure the spring on the governor rod is connected on both ends? Use fresh gas. Good luck.
Drill out idle jet one size at a time those cheap carbs need a little work some times bought a cheap carbs for my generator and surged so I drill one size and ran great use pin drill bits
have several engines with niki can't get surging to stop cleaned carburetor put new one on and still surges have checked heads and valves to no avail
Jim Smith ever get it figured out?
I have a similar engine on my Craftsman with the EXACT SAME ISSUE. It's getting fuel. It's getting spark (I'm assuming since it's running) and there aren't any air/vacuum leaks. I can't figure it out. Maybe I missed something in a jet in the carb (small debris?) or POSSIBLY.... the magnet on the flywheel is too rusty for consistent spark
actually the rust on the magnets on the flywheel won't matter unless it's so thick it's hitting the coil. mine fixed it's self after running it a while might have been dirt.
Broken spark plug. Even though I tested it, there was a crack in the ceramic that caused it to short out when under load. $75 and a month in the shop.
I wonder how they over looked that?
your fuel filter is backwards, but that is not the reason. The OEM versions of those Nikki carbs cost quite a bit. The cheap versions never had ran right. The main jet isn't letting the proper amount of fuel to flow.
The problem is the fuel filter, you filter you have on is for fuel a pump. . You need the small white filter.
oh,,ok,, thanks.
Make sure the gas cap is venting.
I have seen this happen before the gas line was partially clogged from the gas tank to gas filter detach line from carburetor. Make sure gas flows out freely if not replace gas line.
my surge is actually the engine getting a shot of gas thereby momentarily flooding engine can tell by puff of black smoke when it happens
Maybe it's time to tell you intake leak on intake manifold of the intake valve in the head is leaking ive ran into this all the time it's always the intake valve is leaking looks like the intake seat wasn't ground right.
I did the same as you and changed carb got same problem found out to use micro dill bits you take bowl off carb and find the largest bit that will fit in the low speed jet , then the next size that won’t fit cause you want to make hole bigger it the round brass thing to the side of the main jet post just slowly and gently make hole bigger then reassemble it all it should solve problem it not do again with next size bit if you don’t have any micro bits buy them on amazon or eBay they are worth the money
Thank you, they did send two other jets that are bigger, that will be the next thing I try , is to change to the bigger jets.. I hope it helps.
It could be wear in the governor on the inside of the engine, and it can be adjusted.
I had the same problem with mine exact engine. It took trying 2 new carbs and that didn't fix it. I bought a used briggs factory carb problem solved.
the one I did buy was a Chinese model so it could be bad,,
The 2 new onesI bought were both Chinese off ebay..They both did the same thing. I bought a used Briggs carburetor off ebay and it worked fine.
Thanks for the video. Mine is doing it and this helped.
I had the same exact thing and racked my brain for hours on it. Another post here I followed and it was the air/fuel mixture screw on top of carb. Back out 1 1/2 from the bottomed out screw and it worked flawlessly. I did have to add some grease to keep the screw from vibrating and causing the same issue. Even went as far as buying a new carburetor when I didn't need too.
Two things one engine is broken in requiring more fuel on low speed jet requiring drilling, or the govenor slack spring either on the actuator rod or the short one that is behind the plate on the side of engine
Fuel, air, spark. That is what is needed. You have fuel, and you have spark. The mower is choking for air.
Low speed jet
Fuel tank cap vent hole clogged possibly, Gov or carb parts sticking/binding, carb adjust, here are my trouble shooting ideas. I know video is old but hope helps future issues
Do you have those videos still.sure could use some help with mine as well.
@@danielcoulter6523 On my channel jklcksmth booyah
I have the same problem as of today.
Maybe spring on linkage from carburetor back to governor arm is not hooked. Either on carburetor or the governor?
I think it was just dirt because it started working right as I used it a little while.
That fuel filter is on backwards if you didn't know it that's not why it's hot but it dirties up you can't see if it's dirty because it's on the inside not the outside if you turn it around you have to put a new one on
I sold it a long time ago, it started working fine.
Did you try a new small Red or White fuel filter like the one you replaced that was designed to be used on engines with the gravity feed system? The large clear fuel filter is made for engines with a fuel pump & it is most likely too big. Maybe shorten the fuel line too so gas isn't trying to go up hill with the gravity feed system.
Loop
Intake tube might have a crack where air intake is not sufficient.
The carburator has 2 screws get your screw driver an adjust one off the screws an tha serving will go away I had that problem I think it was the air screw
I'm sorry spelled surging wrong
Bad coils could cause performance issues, and no one really ever thinks of that. It may have enough spark to start the engine, but there are videos that show how degrading coils affected the rpm's of an engine. If yours started to work again, good, but it could be getting ready to fail. I'd check the Ohms on your coils with a multimeter. Again, there are videos about that.
No clue. But some of these guys will be able to help I’m sure.
yeah, lots of the guys on here have done this kind of work for quite a while,, thanks for watching,
The fuel lines drooping. I'm sure you probably figured this thing out by now and I'm wasting my time but since it's gravity fed if you're short not fuel line up so it's more straight from the tank to the carburetor it will feed the gas more steadily. Also I seen another video where the guy said since his fuel line was drooping it was in the past of where the hot air is meant to dissipate and it was evaporating the fuel before I could get to the carburetor. But even in that video I think it was because the fuel line was drooping so much it wasn't pouring as steadily as it needs to straight from a tank to the carb.
in this case the tank is lower than the carburetor so I had to put a pump on it, so the drooping doesn't matter, thanks for the comment.
Old note,, but put new carb kit, especially diaphragm. If not that check for leak at the intake manifold or other places air can enter which will cause this due to the wrong fuel/air ratio.
Vacuum leak after carb at intake manifold....if you can get a cigar take a good hit and blow into the carb with everything hooked up and see if you see any smoke escaping...
that's a good idea but I sold it so I am good now.
Take a good hit huh.
My 17.5 Briggs and 17.5 Tecumseh did it and the governor was not set right. Bought both as basket case riders and did the exact same thing you are doing. It could also be an intake leak at the head. I hope you get it figured out without kindling and a few gallons of gas.
lol, the kindling and gas might be a good idea,, I sprayed carb cleaner around the intake gaskets at the block and carb and it didn't make any difference in the way it was running, I will double check the setting of the governor.
by the way the Fuel Filter is Backwards it has an Arrow on it for fuel flow
well, that's probably what was wrong all along.
After reading all the comments (my old 11HP Briggs Stratton Murray tractor had the loss of power backfire puffing situation) first thing was replace the carb, next pull the flywheel, then adjust the valves, replaced the fuel line and filter, nothing has really worked, I also tinkered with the governor a bit and I think that may be an issue because for a while I could actually run the mower and cut grass. The spring on the governor and the linkage spring are two different items. I need to experiment there. Also the fuel filter does seem to be the large clear style and is odd the way it fills and bubbles back so maybe I need to take a look at that possibly bypassing it to make sure that is not causing an issue.
I guess in my case there might have been a little dirt somewhere because after a while it straightened up and ran like it should, I really don't know what was going on with it.
Your govoner spring is missing, broken off. Find it or replace it.
It's in the float
Seriously. All 3 carbs are bad? Come-on.
The answer is more simple that you realize. The answer is those engines surge if the air cleaner box is not installed. The air cleaner box with the air filter, acts as a sort of air flow limiter and this suction or limiting of air flow to the inlet of the carb is required to keep the engine from revving up too high and causing the governor to go wild as it tries to compensate for an engine that wont sit in the rpm range its set for. Put the air box on and I bet it will run fine.
Had the exact same prob. Put the filter housing back on and it fixed it. Thanks
Mine is worse with the air cleaner on.
@@user-tz9dq2vw1v vacuum leak or a leak in some internal seal of the carb.
How about put a real throttle cable going to the governor lever or throttle itself & be done with it??
I have the same problem with my Briggs & Stratton put a new carb on still has same problem. How did you go did you fix the problem yet , Iam yet go go find abit more before a have other go aat it.
actually it sorta fixed it's self after a while.
So I’m at the same spot but I found that if I spray carb cleaner at the area where the carb and intake connect it smooths out 100% for about 10 seconds. Replaced and sealed gasket - no luck. About to remove assembly and look for cracked intake but need to finish yard first
I had one mower where someone had put the wrong bolt in the intake and it went in and broke through where the intake valve was and was sucking air that way.
@@MissouriOldTimer the connection at the head is good. The leak is between carb and intake. I’ll let you know
@@paulkennedy5822 that should be and easy fix.
@@MissouriOldTimer trimmed gasket to fit better, put some sealant on it and now she runs like a champ. I bet that leak is the reason a lot of Inteks surge like they do
@@paulkennedy5822 you may very well be right, my favorite gasket sealer is now and has been for 50 years is Indian head shellac, it don't work for everything but on fiber gaskets it does a great job.
Drill the low metering jet a little bit bigger.. I needs more fuel
Is the plastic looking intake leaking someplace . Have you taken the bowel off any of the carbs after running , to see if stuff is getting in there or water in the tank . I would also try with air cleaner in place or half hand coke it to see if it straightens out any .
yes, I have even taken the new one apart and it looks good but I cleaned it anyway, with carb cleaner and air,
Look at the idle circuit in the carb, it wants to go to idle but there is not enough fuel, so it goes back up in speed, then tries to idle again.
yes, I think there must be something blocking the low side somehow,
Make sure the gas cap vent isn't plugged
Mine don't do it
Mine doing the same thing and same model
Good day Did you ever figure it out , the surging . Mower N Blowers figure out, gas inlet straight is better than curve. Thanks I don't know
Vernon, if you didn't get it yet, there's some things, you may or may not know that might steer you into fixing it.
First of all, (as you may know) these modern engines are all made to qualify for EPA regulations using what the factory calls, "Lean Drop Idle," wherein the jet, whether it's adjustable or not, is set to where the unit will just survive running on the idle circuit. ANY loss-variation of fuel on the negative, or any gain of air on the intake, and you risk it doing that loping idle.
First, look to see if that used one, or either of the Nikki's has an adjustable fuel-idle circuit or an air mixture screw, (sometimes hiding pretty good around the left stud hole).
I'd use whichever carb has adjustable jets of any kind.
If that used one doesn't have adjustable, you definitely want the new Nikki on there. Then make sure, the air intake to air filter assembly is totally sealed on assembling and you have a good air cleaner installed. That will assure, everything is just the way the jets are ported to run properly. If none of that helps, before you do any changes to the port, you should do these things:
1) Switch to ZERO-corn fuel, run it for a half hour or so and see how it does.
2) Check and adjust the valves. I believe that one is 2-3 thousandths, if the spec is 3-5, go 2-4, etc., I always go to 1.5-2 on worn engines. Make sure that troublesome valve cover - to intake tube is not cracked or leaking anywhere.
Finally, look close at all those carbs. Hopefully one of them has a welch plug somewhere on the left side that can be removed. On rare occasions, I've used a torch tip cleaner and (ever so slightly) reamed the tiny hole going into the back of the carb throat just on the other side of the throttle plate. From the start I'd say just clean those tiny holes out, but you have a new carb there, and that shouldn't be dirty? Either way, it's about the only way to correct that.
UNLESS, someone's really messed with it and changed your low-side governor spring? Pretty doubtful, but it's possible?
Good luck. . .
FYI, not messing with you Vernon, been working on these for 50 years, this is the same step by step we'd go through on any customers rig. Very doubtful there's anything wrong with your original carb, it's a very good quality, tough carb.
Good luck.
thanks, those are some good suggestions, surely some of that will fix it.
well, the last ditch fix of drilling the jet orifice out will (if done right) will always work, but it generally means one of the others was overlooked, or, the valves are falling out of adjustment. They are very particular, you have to hold that allen wrench as tight as possible while locking it down, just a smidgen of a movement at that moment can throw it 3 or more thousandths off.
After giving this some thought Vernon, since you've essentially proven it's not the carb, I'd put the original back on and troubleshoot from there. Sure hope you get this, interesting to find out what you finally did Sometimes they're so particular, just cleaning the primary jet tube out, (especially all those microscopic holes that run up and down it's shaft) will often solve it. Those things need every infinitesimal bit of room for fuel flow that is given them when manufactured, they allowed practically zero room for even a thin coat of varnish to build up on them before problems ensue. Good luck!
Could it be the governor spring? Mine ran well with the old carb but the carb leaked. I got a new one. Now it backfires back out of the air intake. Looks like most is shooting into the carb from the breather. I was thinking too much air, but my friend messed with the governor spring and the little screw on the linkage. Could that be the problem? I tried adjusting it all different ways. The engine only doesn't backfire when I have the idle turned way up. Thanks.
@@johnlibonati7807 Make sure the flywheel key has not been sheared by a sudden stoppage or just plain wear. That throws off the timing and timing can cause backfires. Key is right under the flywheel nut.
Could be that the governor needs adjusted or the low idle air mixture adjustment on the carb.
What would keep it from starting?
@@insideoutsideupsidedown2218 That COULD be any of a dozen issues. Bad gas, no gas, plugged filter, bad spark plug, bad coil, bent or broken fly wheel key, fuel pump, and so much more.
what sure is windy in your parts
Not that it's causing your issue, but your fuel filter is on bassackwards.
I sold the mower shortly after the video it started running right , I guess it was a little bit of dirt in the carburetor.
Try a valve adjustment
Spray some starting fluid around your intake gaskets if I races up, replace the gaskets. I mean you tried 3 different carburetors so I'm pretty sure we can rule out any jetting issues. It really sounds like you've got a bad intake gasket. Does it smooth out if you set it to ½ or ¾ choke?
Hello. I had the same problem and found a vacuum leak in the throttle gasket. :) then, it ran fine.
Air leak intake or air lines ?
Or old fuel lines, they will rot on the inside and look fine on the outside.
did you ever figure it out ? that one spring up top didn't look like it was attached on its left end .
I started using it and it smoothed out, but I sold it shortly after that. I don't have it anymore.
90 percent of the time is a fuel starvation issue with the carb jet not letting enough through. More than likely that is it and u don't need to re set the governor
I think so too. I have the same problem and I believe it's a fuel problem too.
Provide gas using something else than the stock gas tank. Mine had something slightly blocking the gas feed from the tank to the line.
it just started working right after I started mowing the yard.
Isn't your fuel filter installed backwards?
it may be but it filters either way, one way you can see the dirt being trapped better. .