Make sure the rod didn’t punch a hold In the bottom of the case causing the lean condition. The clearance is pretty tight sometimes and that can happen. You’ll rebuild it and it will blow up again. It’s either a carb issue (pop off?) or an air leak
Check your base/crank/intake tract gaskets for leaks, sucking in air in these spots will make a lean cylinder. 32.1 is fine for that engine and make sure you're pilot jets are kept clean as they will clog up easily and also lean said cylinder out.👍
if you find oil in the muffler then it is not burning it, Every engine burns different due to carb settings and sea level, Back it off until it runs faster then add more oil to the mix, example lawnboys loved 4 Oz per gallon but echo or stihl wanted 50;1 so the exhaust tells you if it is happy
Well they should have left the oil injection pump system on. Smh never understood why anyone would remove that. And try to run pre mix. It’s not made for that.
One thing to remember is these older air cooled snow engines are default jetted and designed to be operating in the 0F-20F ambient temp range which keeps them much cooler. Running in warmer weather means less dense air and less cooling - running 40:1 is usually a good choice, with one jet size up on the carb - if your two stroke isn't smoking a little you're too lean. Dual carbs are always a danger running pre-mix, any clogging in a jet or in the float needle means you run that cylinder dry which kills it in no time - if you sense a misfire, stop it immediately!
Ex Watercraft 2-stroke tech here. 40:1 or 50:1 is fine with high quality oil. The problem is, you changed the exhaust and intake and ran it at a higher RPM for longer then designed. It leaned it out badly. An exhaust temp gauge (I ran one on all my 2-strokes when desert racing) will let you know if you are hitting piston melting temps. But next to that, go at least 3-5 sizes bigger on one carb, then see how it runs. When you get to the point that it blubbers because it's too rich, then go down one size. When you feel like it's close, then do the same for the other carb. You want both as rich as you can, taking note that the leaner you get, the better they run until they melt the piston. So it's a balance of getting acceptable performance with being as rich as you can get it. Also pull out and read the plugs. This jet, test drive, check plugs, change jet, test again, normally would take me about a half day on a 2-stroke with no baseline. Like if someone changed motors or carbs. Take your time and get it dialed in. Since you are mostly running that thing at WOT, you should be able to get away with only testing at WOT and changing just the main jet, then when that is good, adjust the air/idle screw to get it to idle, and/or move the needle. Quick edit for certification. 2-strokes, and doubly so air-cooled depend on un-burned fuel for cooling. Too hot of combustion temps will cause the piston to expand, and scratch up the cylinder walls. You will normally notice 4 total scratches on the cylinder walls that line up with the piston pin areas as that is the thicker part of the piston and it expands more. If you take running lean too far, normally with a multi cylinder engine with multiple carbs, you will get pre-detonation, normally indicated by a hole in the top of the piston or destruction of the top of the piston. This is really common when one carb gets too little fuel, but the other keep going, so the engine is run past when you should have shut it down. Oil starvation from incorrect pre-mix, I almost have never seen. When I do the piston has scratched up the entire cylinder equally, and you don't get just the 4 big scratches, but it can be hard to tell exactly. Melted/bad rod or crank bearings are a good indicator of lack of oil. As for pre-mix ratio, I have seen older 2-strokes require 20:1, and high performance ones require 50:1. We have better oils then we had 40 years ago, so ratios have changed. A really rich 20:1 will cause oil to build up in the exhaust, lots of smoking, and build up on the plug. If it's not a new engine that specifies 50:1, OR it is an turned race motor, I normally run good old 32:1 with Yamalube R1 or other good off-road oil. I still maintain that in this case of the the failure in this video, the engine's jetting was not correct for the conditions the engine was run under. The water in the fuel may have also been a factor, but the engine needs to be properly jetted to handle the different load it's under, along with the changes to the intake and exhaust.
Great advice! I've been a professional small engine guy for forty one years too. My approach for adjusting the main jet is to start out rich and lean out as previously suggested but do it at no load. Remove the belt (is it belt driven?) and it should "Four cycle" with out a load and smooth out/ "two cycle" under a load. You should be (about) two sizes richer when it just starts to "two cycle" under a load.
You forget aircooled 2 strokes run hotter then their watercooled counterparts in watercraft. So yes 32-40 to 1 would be fine for this engine, this is also the ratio that many ultralight airplane pilots use. A good quality oil for aircooled 2 strokes is a must! I use Power Punch 2 cycle oil when I can get it. Our local supplier is hit and miss.
when you remove restriction from the exhaust of a 2 stroke, it causes a lean condition. you need to rejet the carbs to run fatter to make up for it. i do it with chainsaw all the time
IMO a little extra oil doesn't hurt anything. Might make it smoke a little more and not make peak power, but it generally doesn't cause damage. Id run 32:1 Might also consider running the stock oil injection pump. At least with that both the cylinders get oil no mater what happens with the carbs.
@@bb-ballistics1706 I could see that happening with large amounts of oil in the gas. But you're only talking a few ounces per gallon. Even if it did slightly lean the engine with the extra oil it likely wouldn't sieze/burn up.
When you add more oil you make the engine more lean! I tried tellin yall last time when you arent using oil injection you need to jet up!! You should use the oiler for better crank lubrication especially needed at extended high rpm. If not JET IT UP!!!
Hey John I recommend you might as well replace the crank seals and stuff to make sure there's no leaks and then do a leak down test on a crankcase especially since you had an overheating problem you could have burned out seals and not even know it
What you said at the end of the video is a good plan you need a pretty rich mixture i usually stick with 32:1 but ive had to run 40:1 on a ke100 recently because it was loading up on me too often. You're on the right track with the jetting change its a huge and often over looked part of a two stroke if you run a four stroke lean enough on fuel you can over heat it and cause the same melted piston problem you guys are currently having the way to avoid that with your two stroke is to jet it so fat that it loads up and wont rev then lean it out just lean enough that it revs smoothly again. Thanks guys been watching since 2015 or 2016 and your videos are always fun to watch
I mix all my 2 stroke engines 4 OZ to a gallon of gas. that's around 32 to 1. I have found out that diaphragm carbs last longer stay more pliable and extra oil doesn't hurt anything. More lubrication keeps parts from wearing so bad. Also spark plug is much cheaper than piston and jug. That's just what I have found that works for me anyway. Thanks for bringing me along.
Putting in more oil doesn't hurt performance, just jet accordingly. I like to be around 25:1 on my super rare engine for which there are no parts available at all, 30:1 on others. A bit less oil would probably be fine but why risk it. It's a 2stroke and it needs to smoke. I know good oil isn't cheap nowadays but it's not like you're gonna go through 10 gallons of it in a hovercraft.
I ran Klotz Benol and R50 techniplate at 50:1 in every 2 stroke I ever owned. The key is the carb jetting and reading your spark plugs. Also you guys are going to want to get the silencer section back onto your expansion chamber. Also make sure the inlets for the old oil injection are capped off or JB Welded closed. If those are open that will cause a lean condition and you will be burning down pistons quick.
That to could be one of the problems and plu they have a cooling fan on there for air flow around the heads if they don't have plating to direct the airflow to that back cylinder that will get hotter than the front cylinder
This is typical for a 2 cilinder, the crankseal on that side is leakin, maybe a worn out bearing? the belt pulls pretty hard on that side...makes it run lean on that cilinder...if possible, get some Viton seals, the purple ones, those are more heat resistant....this is not a carb or mix problem, the other cilinder/piston looks undamaged...40 to 1 should do fine, i use 35 to 1 on my 2 stroke racer, but thats a 15k rpm machine...just use full synthetic 2 stroke oil..you could jet up a bit, just to be safe, can always go back
Agreed, I run 40:1 in everything. My snowmobile swapped golf cart has a rear crank seal on clutch side weeping oil but it runs fine. I will eventually get into it, replace the seal and also change the front seal out for good measure
Get the ID numbers off the motor, it is stamped on the clutch side housing-half by the fan, and find the fuel ratio for that motor. Most all two stroke snowmobile motors are 50:1 as long as no up grades to motor or carbs have been done. I have two sleds with the same motor and run 50:1. You'll get it figure out! Good Luck guys!
That cone on the fan outlet is known as stator vanes, in this situation it's used to convert outlet swirl into additional thrust, also making the air exit more laminar way, also contributing to thrust you can think of it as additional counter rotating fan from perspective of airflow.
I've always ran 50 to 1 in all 2 strokes. You are correct with adjusting the jet size. I've always had smoke from the exhaust when rich enough from the jets. They call it a two "smoke" for a reason. Too fat is always better than too lean. What's a set of plugs once in a while.
Adding more oil to a two-stroke creates a lean fuel mixture. Modern two stroke oils can safely be run at 50:1 or more. Since this is a snowmobile engine the carb will set lean for colder temperatures it will need a larger main jet and maybe a richer needle and pilot jet. It seems to idle fine so the pilot maybe fine.
I took the engine out, flipped mine over and took out those runners. I read that it caused a lot more hull damage than they were worth and you’re right try to stick to the grass or water for setting it down if at all possible
You've got aluminum from the melted piston stuck to the cylinder wall. The standard method is to bathe the cylinder lining with muriatic acid (pool acid). It will attack the aluminum and leave the lining alone.
i just have to say it as someone who lives in northern Minnesota i love snowmobiles have worked on a ton of different ones that being said i recommend 32:1 after rebuild most motors run 40:1 mix by oil pump a bit extra doesn't hurt though. Loving watching and looking forward to many more videos to come!
I agree with the leaves... Snowmobile engines aren't meant to run in warm temps also, they are dogs above 35 degrees, I grew up with snowmobiles, and live in the northeast... I know it might be costly, but you should get a liquid cooled engine and don't bother with a fan cooled engine.
Another theory could be the lack of fuel mix going into that cylinder. I've seen pistons crack and break apart from friction heat because of the lack of fuel mix in 2 strokes. Mostly weedeaters and chain saws, but they all work the same. Would check the carb ports thoroughly. As for mixture. I've always done 32:1 and 40:1 for break-in after 8 hours of run time. Then 50:1 every run time after that. Unless it sits for months. Then do 40:1 for 3 to 4 hours and back to 50:1.
you uncorked the exhaust by cutting the tube off and making it go straight out, that made the fuel mix WAY off! when you pulled the plugs, i could see they were completely grey, so it was running WAY LEAN!!! it needs to go up in jet size to make the plugs the correct cardboard brown they should be.
That shouldn’t do anything to it it’s carbureted and doesn’t have an oxygen sensor telling it how you feel and air make sure it has so it’s gonna stay consistent there And if you look that was more like a silencer because it still was straight through like a straight muffler, so realistically, they didn’t cause any pressure change, and if it was, it was very minor most likely that motor had some issues prior to them getting it
More oil means it burns more lean means it runs hotter. Stick to the factory mixture specs. Changing exhaust and making it run higher rpm’s should be totally fine. Make sure it doesn’t draw any false air between the carb and the engine because that will lean out the mixture as well. Exhaust temp monitoring is fine but a bit expensive, the next best thing is monitoring the spark plug temp which is a lot cheaper.
I'd stay around 32:1 or 40:1. Also, replace the crank seals they be the difference between long life or death for your engine and get good seals, too. My cousin had a 2 stroke 4 wheeler, and the crank seals let go in it, and it caused a runaway.
Most of the older engines, especially ski doos, always like 33:1. Also, if it was mine, I'd get those pod filter shielded, because if water gets injested thru the carburetor, it will do the exact same thing!
Use Morettic acid and a Q tip to burn off the aluminum stuck to the jug it will not hurt the cylinder, then hone , the pto side should be Jett a little ritcher it tends to run a little warmer away from the fan 32/1 your safe
The tough part about a hovercraft is you really can't slow down to turn or change direction, you need to be going all out and plan every move out ahead so you can slide into and around everything. I bet it gets better with more practice. OR... And hear me out... Add a second motor purely for lift. Then you can always have the float, and you totally can decelerate to make turns and get through obstacles. I think you should try it.
40 to 1 is a richer mixture in terms of oil. it is 40 parts gas to1 part oil. 50 to 1 is 50 parts gas to 1 part oil. The harder working a 2 stroke engine is, the richer the oil mix needed for lubrication. Many old snowmobile engines actually ran 32 to 1 or richer, some in the 70's even as rich as 16 to 1.
The more oil u add the leaner it makes the fuel on any 2 stroke and definitely should run 32 to 1, check crank seals and intakes, that will make it lean as well if they leak.
Some things to watch out for with 2 strokes and oil/gas mix. - if it's premix, know the mix OR default to 32:1. Then take a plug read to know if you're too lean. -When going from oil injection to premix, you'll want to go up 1/2-1 jet size on the main to account for the differences in molecule size going through the jet orifice. Oil molecules take up the space once occupied by only gas. Great stuff guys! Love where the channel has gone. Keep it up!
You literally have no idea how many times I have tried to educate people on that! I have also seen them just leave open air leaks where injection lines hook up to carbs and or crankcases!
that's why you should always leave the oiler on a 2 cyl even if you run 2t gas if one carb is dirty and isn't giving gas to the cyl then your not gonna have a good time, another thing with self-oilers is they sometimes oil the main bearings and they won't get enough oil and can blow out, had it happens on an RM250 that someone did an oiler delete, if you do then make sure to run all lines into the crankcase if that has a main bearing oiler
I've damaged many a 2 stroke running 87. When I started using 91 in 2 strokes, I stopped having problems. 2 strokes run hotter than 4 and need the extra detination/knock resistance of the higher octane.
The safest course of action is always to mix at an oil-rich mixture (i use 25:1) and then adjust carb settings for that. Then if a lesser oil mixture is used, there will only ever be more fuel, which is not going to hurt anything. Always start too rich on fuel.
On hovercrafts the rear cylinder always tens to run hot so you may have to jet it differently we used to have a shelf of melted pistons before we went water cold
50 parts gas to 1 part oil doesn't seem oily enough to me. I'd go 20 parts gas to 1 part oil. Get a lot of oil in those cylinders. You may foul out some plugs. But, that's no biggie. If that happens, try 32 parts gas to 1 part oil. Err on the side of caution. Spark plugs are a lot cheaper than pistons, heads, and jugs.
I have Craftsman saw that has a Poulan exact model counterpart, one says 32-1 and the other 50-1, always used 32-1 bc you'll fair better with more oil -- always,always,always verify crankcase seals for pressure and vacuum.
Check you crank seals. If they leak it will lean the out the engine. My experience has been that the PTO side wears quicker. Especially if your bearings are wearing out.
Anywhere from 50:1 to 35:1 is fine on a good strong running 2 stroke and wouldn’t affect the overall performance of the machine a lot of people will argue that but I grew up building 2 stroke dirt bike engines and learned if they are built properly it’s all about carburetor tuning.
29:07 This is a severe duty application. 50:1 would be oil starving in a light duty application like the snowmobile it came out of. Given that this engine is operating under constant, heavy load at all times, I would give it no thinner than 25:1, and preferably 15:1. It's gonna smoke like it's coal fired; that's how you know it isn't going to blow up again. You may have to adjust the carbs somewhat to get it running nicely on such an oil heavy fuel, but nobody's ever blown a 2-stroke because they ran too much oil through it.
@@skmetal7 It isn't the RPMs. The issue is that the engine is under a constant, heavy load. It's having to work hard the ENTIRE time it's in operation. This engine is not designed for such a task. It is designed for a fairly light load where it's only having to deliver max output on occasion and is otherwise at partial power. When you're riding a snowmobile you're generally not bogging the engine down making it pull as hard as it can the whole time, even if you're WOT blasting a flat area. Further exacerbating this is temperature. When you work an engine super hard, you're gonna get it hot. Snowmobile engines aren't all that good at cooling themselves off because they're designed to operate in extremely low ambient temperatures. Even in a fairly light duty situation...IE someone's shoved one in a Yerf Dog...they're going to be highly prone to overheating. When they're being asked to pull most, if not all, of their rated power continuously like in this hovercraft they're not gonna be able to cope. We see this play out in the failure; the cylinder that died was furthest from the fan and it had evidence of running MUCH hotter than the other jug did. This engine needs a LOT of oil run through it if it's going to survive on a hovercraft. The engine they took off was designed for this purpose and they could have that thing WFO from now till doomsday it won't care. But this engine WILL care. Might not be a bad idea for the guys to rework the cooling on it, too, and instead of relying on that dinky little fan the engine has use the big-ass fan it's turning to pull more cooling air through it.
Was you guys using the right 2 stroke oil? Their is a marine version that is specifically used for water cooled engines and a air cooled version that is specifically designed for the higher temps that air-cooled 2 strokes generate.
With two strokes make sure you have no intake leaks and your jetting is correct those two things are probably as important or more important than your mix
Fellas, raced two stroke motorcycles from 1973 to 1992. Always use 32-1 and jet it using plug readings to get to proper fuel air mixture. Run good 2 stroke oil Pressure test crankcase to ensure no leaks. Use new gaskets.
Gordon Jennings wrote the 2 Stroke Designers Handbook, everything you never wanted to know about building 2 stroke engines to the ninth degree. Results of oil ratio testing Suzuki PE 250 single @7000 rpm with varying oil ratios, 15:1=27.3hp, 20:1 = 26.9 hp, 30:1 = 24.5 hp. More oil cooler running engine, cleaner running engine and more HP 50:1 sucks
was thinking the same, I used to work at a Suzuki shop in the late 70s to mid 80s and at that time most 2 strokes were at 20 to 1 and maybe 32 to 1 at that time was as lean as you wanted to go.
I believe that in the first video when you got the Rotax twin you removed the oil injection pump. The engine is designed to run with a certain amount of oil being pumped into cylinders as per the rpm. The higher the rpm the more oil. When you are running a premix, when you are wide open you could be leaned out from 40 or 50 to 1 to as much as 100 to 1. Also it also designed to run in a colder enviroment. To keep the pto side cooler you could run a colder plug on that side. You could also go to a single carb setup which will maybe lose some performance but remove the possibility of a lean carb on one side.
doesnt really make sense, yes, the oil injector gives more oil, on higher rpm, but thats just because the amount of gas through the carb is higher too, ideally it would give a solid mix, on every rpm, reading the rest of your comment, well, no offence, but i would never let you do anything on any 2 stroke😅
oil injection on 2 stroke is on a 1 to 1 pumping ratio - i.e gas oil ratio never changes at any rpm - designed/built and wrote 2 stroke engine manuals to include service warranty training for several years
Guess I was misinformed. I hate 2 strokes and won't work on them. Quit working on snowmobiles years ago. Google the question " Does a 2 stroke premix run the same gas/oil ratio at all rpms
Too much oil causes a lean condition. Been playing with little two-stroke mopeds for a lot of years. Amsoil Saber 80:1. Also the engine needs to be tuned correctly for warmer, denser air.
I would look into getting or making an intake silencer (airbox) for that unit. A plenum to draw away from the fan airflow maybe a good idea as well. I suppose your hovercraft contact would know what works here.
It looks more like it hung a ring than melted a piston. Meaning the ring caught on one of the ports and snapped the top of the piston off, causing all the rest of the damage. Usually a melted piston develops a hole in the top of the piston that looks literally like molten metal.
After watching the whole video it seems like you've potentially found the culprit. I've found it's always good practice to start with fresh plugs and do a plug chop (while there's heat in the pipe go WOT & hit the kill switch then read the plugs) while tuning, starting with richer jets incrementally reducing jet size until the insulator on the plug is a nice golden/caramel brown color, I typically leave 2ts a little rich as a safety net incase an intake boot/gasket or crank seal decides to develop a leak that could cause a lean condition and it also help with cooling. A lot of people don't do it but make sure when you clean the carbs to remove the needle jet from the carb, if there's any junk in between the needle jet and carb body it wont supply fuel properly. It'd probably also be a good idea to run a colder plug than recommended from the factory for this use case.
Two strokes are quite sensitive to exhaust tuning to get proper cylinder scavenging too, hacking off the exhaust might have had a hand in the failure as well, The water in the carb would definately lean it out too. I don't think the failure had anything to do with lack of lubrication and more to do with heat. Low octane fuel also burns hotter, and maybe check the heat range of the plugs too, might have been getting some detonation.
It being a snowmobile engine previously Ill bet the motor came from somewhere high altitude and had small jets in it to deal with the thin air. Bring it near sea level and boom too much air AKA lean. low oil/fuel ratio like 50:1 is more likely going to cause bottom end issues not top. I personally run 32:1-40:1 in my SCAT 1 because reliability and longevity are more important than performance for me, either way I wouldn't expect any issues 32:1 - 50:1
John and Ike,,, Your on the right track with a problem with fueling.. It's not the ratio. You probably have another problem contributing to this... You can also read the top of the pistons to get an idea of fueling. Quick Internet search will show you this! Just remember 40:1 and 50:1 have been used on 2 strokes for a very long time!! Don't think it's your mix that's causing you problems.
Couple things to add to the very informative comments here, there was only one outer wear on one filter, will change the air fuel. And the other thing, water can run down your throttle cables and put water in the carb right down the needle. Jet fatter and stay heavy on oil. Plugs are much easier to clean and change while you lean it out a little bit. I've had 6 banshees and never blown one up with very heavy use by having big carbs and always jetted rich (carry spare plugs) also, use higher octane for the quality of fuel as much as octane. Have blown up 2 strokes but after I learned how to keep them alive I've had better luck than most, running 10 years on my current banshee and it is not babied. Maybe a little down on power but still a one kick machine. Have to pull it inside before it snows up here in minnesota! I also use nothing but amsoil for mix, have had very good luck with it.
What 2-stroke oil are you using? Get oil meant for aircooled snowmobiles. 2-stroke oils have different heatranges depending on engine type and if its a air- or watercooled engine. The wrong oil could be quite ineffective.
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Make sure the rod didn’t punch a hold In the bottom of the case causing the lean condition. The clearance is pretty tight sometimes and that can happen. You’ll rebuild it and it will blow up again. It’s either a carb issue (pop off?) or an air leak
Check your base/crank/intake tract gaskets for leaks, sucking in air in these spots will make a lean cylinder. 32.1 is fine for that engine and make sure you're pilot jets are kept clean as they will clog up easily and also lean said cylinder out.👍
Seriously Ike CALL MY MOM!
if you find oil in the muffler then it is not burning it, Every engine burns different due to carb settings and sea level, Back it off until it runs faster then add more oil to the mix, example lawnboys loved 4 Oz per gallon but echo or stihl wanted 50;1 so the exhaust tells you if it is happy
I have a whole bunch of 377 or 380 skidoo motor parts if you need any
Fuel/oil mix don't matter if the carbs aren't jetted rich enough. I always prefer to see a little blue smoke out of a 2 stroke.
Bingo
yea . with that being an old air-cooled snowmobile engine(used in the "summertime" It should have been some blue smoke coming from that engine...
And if you're ADDING oil, you need to up the jetting at the same time or you're leaning it out further.
Well they should have left the oil injection pump system on. Smh never understood why anyone would remove that. And try to run pre mix. It’s not made for that.
One thing to remember is these older air cooled snow engines are default jetted and designed to be operating in the 0F-20F ambient temp range which keeps them much cooler. Running in warmer weather means less dense air and less cooling - running 40:1 is usually a good choice, with one jet size up on the carb - if your two stroke isn't smoking a little you're too lean. Dual carbs are always a danger running pre-mix, any clogging in a jet or in the float needle means you run that cylinder dry which kills it in no time - if you sense a misfire, stop it immediately!
Ex Watercraft 2-stroke tech here. 40:1 or 50:1 is fine with high quality oil. The problem is, you changed the exhaust and intake and ran it at a higher RPM for longer then designed. It leaned it out badly. An exhaust temp gauge (I ran one on all my 2-strokes when desert racing) will let you know if you are hitting piston melting temps. But next to that, go at least 3-5 sizes bigger on one carb, then see how it runs. When you get to the point that it blubbers because it's too rich, then go down one size. When you feel like it's close, then do the same for the other carb. You want both as rich as you can, taking note that the leaner you get, the better they run until they melt the piston. So it's a balance of getting acceptable performance with being as rich as you can get it. Also pull out and read the plugs. This jet, test drive, check plugs, change jet, test again, normally would take me about a half day on a 2-stroke with no baseline. Like if someone changed motors or carbs. Take your time and get it dialed in. Since you are mostly running that thing at WOT, you should be able to get away with only testing at WOT and changing just the main jet, then when that is good, adjust the air/idle screw to get it to idle, and/or move the needle.
Quick edit for certification. 2-strokes, and doubly so air-cooled depend on un-burned fuel for cooling. Too hot of combustion temps will cause the piston to expand, and scratch up the cylinder walls. You will normally notice 4 total scratches on the cylinder walls that line up with the piston pin areas as that is the thicker part of the piston and it expands more.
If you take running lean too far, normally with a multi cylinder engine with multiple carbs, you will get pre-detonation, normally indicated by a hole in the top of the piston or destruction of the top of the piston. This is really common when one carb gets too little fuel, but the other keep going, so the engine is run past when you should have shut it down.
Oil starvation from incorrect pre-mix, I almost have never seen. When I do the piston has scratched up the entire cylinder equally, and you don't get just the 4 big scratches, but it can be hard to tell exactly. Melted/bad rod or crank bearings are a good indicator of lack of oil.
As for pre-mix ratio, I have seen older 2-strokes require 20:1, and high performance ones require 50:1. We have better oils then we had 40 years ago, so ratios have changed. A really rich 20:1 will cause oil to build up in the exhaust, lots of smoking, and build up on the plug. If it's not a new engine that specifies 50:1, OR it is an turned race motor, I normally run good old 32:1 with Yamalube R1 or other good off-road oil.
I still maintain that in this case of the the failure in this video, the engine's jetting was not correct for the conditions the engine was run under. The water in the fuel may have also been a factor, but the engine needs to be properly jetted to handle the different load it's under, along with the changes to the intake and exhaust.
This guy knows his onions
Great advice! I've been a professional small engine guy for forty one years too. My approach for adjusting the main jet is to start out rich and lean out as previously suggested but do it at no load. Remove the belt (is it belt driven?) and it should "Four cycle" with out a load and smooth out/ "two cycle" under a load. You should be (about) two sizes richer when it just starts to "two cycle" under a load.
Backyard guy here, I thought for sure leaned it out a lot by cutting the end of the muffler off and emptying the packing out. Bigger jets!
What do you think about the metal shavings that fell in the pipe when they Sawzalled of off being sucked into the motor on the negative pulse?
You forget aircooled 2 strokes run hotter then their watercooled counterparts in watercraft. So yes 32-40 to 1 would be fine for this engine, this is also the ratio that many ultralight airplane pilots use.
A good quality oil for aircooled 2 strokes is a must! I use Power Punch 2 cycle oil when I can get it. Our local supplier is hit and miss.
Regarding fuel mix ratio: Ask the ultralight flyers. Their life literally depends on the motor running, and a lot of them use Rotax engines.
Yeah but the engines they use are built different to a snowmobile engine so their advice might be wrong for the application.
@@dylanzrim3635 Maybe some... I see a ton of only slightly modified sled engines. Yamaha Apex is a popular option.
The Rotax 470/503 is a very popular ultralight/Gyro engine.
I aways forget about how cool hovercrafts are...
Snowvercraft!
They're handy when you've got to go PLACES YOU CAN'T EVEN WALK.
.. Y'know?
Y’all should build one….
when you remove restriction from the exhaust of a 2 stroke, it causes a lean condition. you need to rejet the carbs to run fatter to make up for it. i do it with chainsaw all the time
❤
IMO a little extra oil doesn't hurt anything. Might make it smoke a little more and not make peak power, but it generally doesn't cause damage. Id run 32:1
Might also consider running the stock oil injection pump. At least with that both the cylinders get oil no mater what happens with the carbs.
Adding more oil can actually make it run lean on the air to fuel ratio. Because you're diluting the fuel down with oil.
@@bb-ballistics1706 I could see that happening with large amounts of oil in the gas. But you're only talking a few ounces per gallon. Even if it did slightly lean the engine with the extra oil it likely wouldn't sieze/burn up.
When you add more oil you make the engine more lean! I tried tellin yall last time when you arent using oil injection you need to jet up!! You should use the oiler for better crank lubrication especially needed at extended high rpm. If not JET IT UP!!!
Hey John I recommend you might as well replace the crank seals and stuff to make sure there's no leaks and then do a leak down test on a crankcase especially since you had an overheating problem you could have burned out seals and not even know it
I was going to say the same thing. A leak-down test is a must after a rebuild.
ruclips.net/video/tOZL01I5g1s/видео.html
What you said at the end of the video is a good plan you need a pretty rich mixture i usually stick with 32:1 but ive had to run 40:1 on a ke100 recently because it was loading up on me too often. You're on the right track with the jetting change its a huge and often over looked part of a two stroke if you run a four stroke lean enough on fuel you can over heat it and cause the same melted piston problem you guys are currently having the way to avoid that with your two stroke is to jet it so fat that it loads up and wont rev then lean it out just lean enough that it revs smoothly again. Thanks guys been watching since 2015 or 2016 and your videos are always fun to watch
I mix all my 2 stroke engines 4 OZ to a gallon of gas. that's around 32 to 1. I have found out that diaphragm carbs last longer stay more pliable and extra oil doesn't hurt anything. More lubrication keeps parts from wearing so bad. Also spark plug is much cheaper than piston and jug. That's just what I have found that works for me anyway. Thanks for bringing me along.
Putting in more oil doesn't hurt performance, just jet accordingly. I like to be around 25:1 on my super rare engine for which there are no parts available at all, 30:1 on others.
A bit less oil would probably be fine but why risk it. It's a 2stroke and it needs to smoke. I know good oil isn't cheap nowadays but it's not like you're gonna go through 10 gallons of it in a hovercraft.
my mentality with two strokes was always that there needs to be at the very least a bit of blue smoke coming out of the exaust
When in doubt, enough oil to smoke out mosquitoes is enough oil to keep it lubricated.
My experience with 2 stroke snowmobile engines and dirtbike engines is to air on the Rich side always worked for me anyway
I'm with ya on that one,,I've always mixed mine a little heavy,,if I didn't see a little bit of smoke,,I'd put more
I ran Klotz Benol and R50 techniplate at 50:1 in every 2 stroke I ever owned. The key is the carb jetting and reading your spark plugs. Also you guys are going to want to get the silencer section back onto your expansion chamber. Also make sure the inlets for the old oil injection are capped off or JB Welded closed. If those are open that will cause a lean condition and you will be burning down pistons quick.
I think when you cutt the exhaust you have taken out the catalytic and then its needs more fuel because better flow
That to could be one of the problems and plu they have a cooling fan on there for air flow around the heads if they don't have plating to direct the airflow to that back cylinder that will get hotter than the front cylinder
32:1, castor based oil, proper jetting, proper pipe length,diameter, etc.👍👍
This is typical for a 2 cilinder, the crankseal on that side is leakin, maybe a worn out bearing? the belt pulls pretty hard on that side...makes it run lean on that cilinder...if possible, get some Viton seals, the purple ones, those are more heat resistant....this is not a carb or mix problem, the other cilinder/piston looks undamaged...40 to 1 should do fine, i use 35 to 1 on my 2 stroke racer, but thats a 15k rpm machine...just use full synthetic 2 stroke oil..you could jet up a bit, just to be safe, can always go back
Agreed, I run 40:1 in everything. My snowmobile swapped golf cart has a rear crank seal on clutch side weeping oil but it runs fine. I will eventually get into it, replace the seal and also change the front seal out for good measure
Get the ID numbers off the motor, it is stamped on the clutch side housing-half by the fan, and find the fuel ratio for that motor. Most all two stroke snowmobile motors are 50:1 as long as no up grades to motor or carbs have been done. I have two sleds with the same motor and run 50:1. You'll get it figure out! Good Luck guys!
That cone on the fan outlet is known as stator vanes, in this situation it's used to convert outlet swirl into additional thrust, also making the air exit more laminar way, also contributing to thrust you can think of it as additional counter rotating fan from perspective of airflow.
I've always ran 50 to 1 in all 2 strokes. You are correct with adjusting the jet size. I've always had smoke from the exhaust when rich enough from the jets. They call it a two "smoke" for a reason. Too fat is always better than too lean. What's a set of plugs once in a while.
Adding more oil to a two-stroke creates a lean fuel mixture. Modern two stroke oils can safely be run at 50:1 or more. Since this is a snowmobile engine the carb will set lean for colder temperatures it will need a larger main jet and maybe a richer needle and pilot jet. It seems to idle fine so the pilot maybe fine.
Truly nothing warms my heart more then a group of good ole boys working on a project!!!
I took the engine out, flipped mine over and took out those runners. I read that it caused a lot more hull damage than they were worth and you’re right try to stick to the grass or water for setting it down if at all possible
Also you should maybe replace the crank seals because if they go bad they can draw in air and cause a lean situation
40:1 has always worked for me on the 503 rotax motors. Crankseals/bearings should be checked along with the carb also before replacing only topend.
Hovercraft series and the king midget series had me stopping everything and watching wherever I'm at....here for it!
You've got aluminum from the melted piston stuck to the cylinder wall. The standard method is to bathe the cylinder lining with muriatic acid (pool acid). It will attack the aluminum and leave the lining alone.
NO OIL IN THE CRANK CASE. Rotax motors need to have a oil tank to cycle oil through the crank case even if the the oil pump is unhooked.
i just have to say it as someone who lives in northern Minnesota i love snowmobiles have worked on a ton of different ones that being said i recommend 32:1 after rebuild most motors run 40:1 mix by oil pump a bit extra doesn't hurt though. Loving watching and looking forward to many more videos to come!
Pretty sure you overheated the engine on the first episode. Do a replay and see how many leaves where plugging the cooling fan intake.
New engine had a cooling fan on it. That large round opening on the front of it I believe
@@jordananderson8299
@@jordananderson8299 In the first episode that cooling fan mesh was plugged up on the front of the engine. As well as the main power fan.
@@Taterchip871Yeah, I was cringing when I saw the leaves plugging the cooling fan intake and they switched drivers and kept going.
I agree with the leaves... Snowmobile engines aren't meant to run in warm temps also, they are dogs above 35 degrees, I grew up with snowmobiles, and live in the northeast... I know it might be costly, but you should get a liquid cooled engine and don't bother with a fan cooled engine.
Another theory could be the lack of fuel mix going into that cylinder. I've seen pistons crack and break apart from friction heat because of the lack of fuel mix in 2 strokes. Mostly weedeaters and chain saws, but they all work the same. Would check the carb ports thoroughly. As for mixture. I've always done 32:1 and 40:1 for break-in after 8 hours of run time. Then 50:1 every run time after that. Unless it sits for months. Then do 40:1 for 3 to 4 hours and back to 50:1.
you uncorked the exhaust by cutting the tube off and making it go straight out, that made the fuel mix WAY off! when you pulled the plugs, i could see they were completely grey, so it was running WAY LEAN!!! it needs to go up in jet size to make the plugs the correct cardboard brown they should be.
Also running a more oil rich mix actually makes the mix "fuel lean" because you are replacing the fuel with oil.
That shouldn’t do anything to it it’s carbureted and doesn’t have an oxygen sensor telling it how you feel and air make sure it has so it’s gonna stay consistent there And if you look that was more like a silencer because it still was straight through like a straight muffler, so realistically, they didn’t cause any pressure change, and if it was, it was very minor most likely that motor had some issues prior to them getting it
At 24:25 that wasn't the only thing uncorked!
💨💨💨🤭@@mattconboy8490
More oil means it burns more lean means it runs hotter. Stick to the factory mixture specs. Changing exhaust and making it run higher rpm’s should be totally fine. Make sure it doesn’t draw any false air between the carb and the engine because that will lean out the mixture as well. Exhaust temp monitoring is fine but a bit expensive, the next best thing is monitoring the spark plug temp which is a lot cheaper.
“Ya I almost burnt the shop down …three times today” 😮 😂
I'd stay around 32:1 or 40:1. Also, replace the crank seals they be the difference between long life or death for your engine and get good seals, too. My cousin had a 2 stroke 4 wheeler, and the crank seals let go in it, and it caused a runaway.
"maybe it is hitting a valve" 🤣
Most of the older engines, especially ski doos, always like 33:1. Also, if it was mine, I'd get those pod filter shielded, because if water gets injested thru the carburetor, it will do the exact same thing!
You can run these engines on pre mix if you mod it correctly (Jets, block off plate, etc.) I'd highly recommend going back to the injection pump.
Use Morettic acid and a Q tip to burn off the aluminum stuck to the jug it will not hurt the cylinder, then hone , the pto side should be Jett a little ritcher it tends to run a little warmer away from the fan 32/1 your safe
Use mueradic acid on a rag to remove aluminum from jug but only inside sleeve
Check the crank seals on the rebuild, bad seals will cause lean out. And i would start with a 32:1, if it fouls out plugs move to 40:1.
The tough part about a hovercraft is you really can't slow down to turn or change direction, you need to be going all out and plan every move out ahead so you can slide into and around everything. I bet it gets better with more practice.
OR... And hear me out... Add a second motor purely for lift. Then you can always have the float, and you totally can decelerate to make turns and get through obstacles.
I think you should try it.
Some are set up this way
It looks like it handles like a jet ski. You really only get turn when your in higher rpm
Sounds like a cool challenge. Some creative fabrication, and it would make a cool couple episodes in the Hovercraft saga.
One often overlooked aspects of fuel oil mix is it changes the air fuel ratio at the same time.
40 to 1 is a richer mixture in terms of oil. it is 40 parts gas to1 part oil. 50 to 1 is 50 parts gas to 1 part oil. The harder working a 2 stroke engine is, the richer the oil mix needed for lubrication. Many old snowmobile engines actually ran 32 to 1 or richer, some in the 70's even as rich as 16 to 1.
The more oil u add the leaner it makes the fuel on any 2 stroke and definitely should run 32 to 1, check crank seals and intakes, that will make it lean as well if they leak.
Some things to watch out for with 2 strokes and oil/gas mix.
- if it's premix, know the mix OR default to 32:1. Then take a plug read to know if you're too lean.
-When going from oil injection to premix, you'll want to go up 1/2-1 jet size on the main to account for the differences in molecule size going through the jet orifice. Oil molecules take up the space once occupied by only gas.
Great stuff guys! Love where the channel has gone. Keep it up!
oil rich and check plugs, plugs don't lie
You literally have no idea how many times I have tried to educate people on that! I have also seen them just leave open air leaks where injection lines hook up to carbs and or crankcases!
Great explanation.
I was always told to use high octane fuel and just mix your own. We use small 2 strokes in our 1/5 scale rc's
@@fishininjun I use 32:1 with 110 octane and klotz premix in my baja 1/5th scale.35cc Taylor engine.
50:1 is for outboards. That engine needs more oil and appropriate jetting to survive running in warmer temps. Remember it's a snowmobile engine.
"maybe it's hittin' a valve" baaaahahaha goooood one dude
and out of blinker fluid
the 289 dude's video was about getting gas that had diesel mix in it from the station right by him.
Thnx.Wondered by the title what went wrong.
he's still not real sure. but seemed to be bad gas.@@bryduhbikeguy
@thunderhead289
thank you for helping and old guy out sir.
he's a good show to watch.@@IGrocker
On the bright side your lawn is now de-thatched and cleaned.
that's why you should always leave the oiler on a 2 cyl even if you run 2t gas if one carb is dirty and isn't giving gas to the cyl then your not gonna have a good time, another thing with self-oilers is they sometimes oil the main bearings and they won't get enough oil and can blow out, had it happens on an RM250 that someone did an oiler delete, if you do then make sure to run all lines into the crankcase if that has a main bearing oiler
I've damaged many a 2 stroke running 87. When I started using 91 in 2 strokes, I stopped having problems. 2 strokes run hotter than 4 and need the extra detination/knock resistance of the higher octane.
The safest course of action is always to mix at an oil-rich mixture (i use 25:1) and then adjust carb settings for that. Then if a lesser oil mixture is used, there will only ever be more fuel, which is not going to hurt anything. Always start too rich on fuel.
On hovercrafts the rear cylinder always tens to run hot so you may have to jet it differently we used to have a shelf of melted pistons before we went water cold
50 parts gas to 1 part oil doesn't seem oily enough to me. I'd go 20 parts gas to 1 part oil. Get a lot of oil in those cylinders. You may foul out some plugs. But, that's no biggie. If that happens, try 32 parts gas to 1 part oil. Err on the side of caution. Spark plugs are a lot cheaper than pistons, heads, and jugs.
I think the reason the rudders go all the way to the left is because it acts as an air break when it is fully engaged
I have Craftsman saw that has a Poulan exact model counterpart, one says 32-1 and the other 50-1, always used 32-1 bc you'll fair better with more oil -- always,always,always verify crankcase seals for pressure and vacuum.
You can use muriatic acid to remove the piston transfer from the cylinder
Check you crank seals. If they leak it will lean the out the engine. My experience has been that the PTO side wears quicker. Especially if your bearings are wearing out.
Anywhere from 50:1 to 35:1 is fine on a good strong running 2 stroke and wouldn’t affect the overall performance of the machine a lot of people will argue that but I grew up building 2 stroke dirt bike engines and learned if they are built properly it’s all about carburetor tuning.
yeah id say with not useing the oil pump they should of jumped a few jet sizes
These are the kind of vids , i luv from you guys , complete random chaos.
i think that cone bit is to counter act the twisting motion that propeller creates
Ask Rotax. These engines are used on ultralight aircraft so they must be pretty reliable. It seems the manufacturer would be the best source for info.
snowmobiles usually aren't rode just pegged wide open. you have to run a richer mixture, just for the sake of helping cooling.
29:07 This is a severe duty application. 50:1 would be oil starving in a light duty application like the snowmobile it came out of.
Given that this engine is operating under constant, heavy load at all times, I would give it no thinner than 25:1, and preferably 15:1. It's gonna smoke like it's coal fired; that's how you know it isn't going to blow up again. You may have to adjust the carbs somewhat to get it running nicely on such an oil heavy fuel, but nobody's ever blown a 2-stroke because they ran too much oil through it.
they could probably add more pitch to the blades to get the rpms lower.
@@skmetal7 It isn't the RPMs. The issue is that the engine is under a constant, heavy load. It's having to work hard the ENTIRE time it's in operation. This engine is not designed for such a task. It is designed for a fairly light load where it's only having to deliver max output on occasion and is otherwise at partial power.
When you're riding a snowmobile you're generally not bogging the engine down making it pull as hard as it can the whole time, even if you're WOT blasting a flat area.
Further exacerbating this is temperature. When you work an engine super hard, you're gonna get it hot. Snowmobile engines aren't all that good at cooling themselves off because they're designed to operate in extremely low ambient temperatures. Even in a fairly light duty situation...IE someone's shoved one in a Yerf Dog...they're going to be highly prone to overheating. When they're being asked to pull most, if not all, of their rated power continuously like in this hovercraft they're not gonna be able to cope. We see this play out in the failure; the cylinder that died was furthest from the fan and it had evidence of running MUCH hotter than the other jug did.
This engine needs a LOT of oil run through it if it's going to survive on a hovercraft. The engine they took off was designed for this purpose and they could have that thing WFO from now till doomsday it won't care. But this engine WILL care.
Might not be a bad idea for the guys to rework the cooling on it, too, and instead of relying on that dinky little fan the engine has use the big-ass fan it's turning to pull more cooling air through it.
That's why I run 40:1. 50:1 will wreak havoc on every engine you use that mix ratio on, big size/displacement or not
Was you guys using the right 2 stroke oil? Their is a marine version that is specifically used for water cooled engines and a air cooled version that is specifically designed for the higher temps that air-cooled 2 strokes generate.
With two strokes make sure you have no intake leaks and your jetting is correct those two things are probably as important or more important than your mix
Check crank seal too
Ok... Ike sniffing flowers is my new screen saver! LOLOLOL!
Fellas, raced two stroke motorcycles from 1973 to 1992.
Always use 32-1 and jet it using plug readings to get to proper fuel air mixture.
Run good 2 stroke oil
Pressure test crankcase to ensure no leaks. Use new gaskets.
32/1 with crap oil MAYBE. THAT WILL CARBON THE WALLS, BREAK OFF AND SCORE YOUR PISTON. THE OIL NOW IS NOT FROM 1970.. come on. really
Most standard 2 stroke oils are 32 to 1 some high end synthetics are 50 or even 100 to 1. I would get the Skidoo oil and mix it 32 to 1
Gordon Jennings wrote the 2 Stroke Designers Handbook, everything you never wanted to know about building 2 stroke engines to the ninth degree.
Results of oil ratio testing
Suzuki PE 250 single @7000 rpm with varying oil ratios, 15:1=27.3hp, 20:1 = 26.9 hp, 30:1 = 24.5 hp.
More oil cooler running engine, cleaner running engine and more HP
50:1 sucks
Interesting, I didn't think it would be that big of a difference.
Those seem like really rich mixtures. Would the difference in oil technology from 1973 to now explain why we don't see those ratios recommended?
was thinking the same, I used to work at a Suzuki shop in the late 70s to mid 80s and at that time most 2 strokes were at 20 to 1 and maybe 32 to 1 at that time was as lean as you wanted to go.
that vortex cone was there so that the air went into a spiral out of the prop making it aim the blast
I believe that in the first video when you got the Rotax twin you removed the oil injection pump. The engine is designed to run with a certain amount of oil being pumped into cylinders as per the rpm. The higher the rpm the more oil. When you are running a premix, when you are wide open you could be leaned out from 40 or 50 to 1 to as much as 100 to 1. Also it also designed to run in a colder enviroment. To keep the pto side cooler you could run a colder plug on that side. You could also go to a single carb setup which will maybe lose some performance but remove the possibility of a lean carb on one side.
Idk every machine I’ve ever had, had the oil injection disconnected and ran fine on 40:1
doesnt really make sense, yes, the oil injector gives more oil, on higher rpm, but thats just because the amount of gas through the carb is higher too, ideally it would give a solid mix, on every rpm, reading the rest of your comment, well, no offence, but i would never let you do anything on any 2 stroke😅
Dosen't the rotex inject a little oil into the end of the crank?
oil injection on 2 stroke is on a 1 to 1 pumping ratio - i.e gas oil ratio never changes at any rpm - designed/built and wrote 2 stroke engine manuals to include service warranty training for several years
Guess I was misinformed. I hate 2 strokes and won't work on them. Quit working on snowmobiles years ago. Google the question " Does a 2 stroke premix run the same gas/oil ratio at all rpms
Yeah running low grade gas can cause issue's up here in Canada we run 91 octane in our snowmachines
You guys need to take this to a beach that is where a hovercraft truly shines!
lol have you seen heavy d sparks video where they wrecked a hovercraft on a beach? lol
They still suck
Perfect for Busco Beach!
Need a way to keep the leafs out of the cooling fan too.. hopefully it’s back!
Ran 50 to 1 in all 2 strokes never had a problem for 62 years. Chain saw, snowblower, snowmobile, jet ski, dirt bike
And remember, the ultimate hovercraft is one that's full of eels.
Good Python reference!
You fried the rings, now me and the mad scientist have to put it back together.
You can tell how much fun you have been having by all the leaf or lack of leafs are around 😂
Oil mixture is usually 50 to 1 but more oil does not hurt will only foul more plugs and smoke more ....
Too much oil causes a lean condition. Been playing with little two-stroke mopeds for a lot of years. Amsoil Saber 80:1. Also the engine needs to be tuned correctly for warmer, denser air.
You would be wrong..terrible advice.
it's 25:1 every time if you want it to last but you need to use ashless oil. TCH3 or something is the spec (here in Australia)
I would look into getting or making an intake silencer (airbox) for that unit. A plenum to draw away from the fan airflow maybe a good idea as well. I suppose your hovercraft contact would know what works here.
It’s also the piston the furthest from the fan. I think it’s getting too hot. Sleds usually run in -15C to -30C
been running 40:1 Motul for last 15years on the same top end on my glamis/dez kx250. never ran anything else on all of our 2Ts.
I run 50/1 oil in all 2 strokes ALL the time. Never had a problem.
It looks more like it hung a ring than melted a piston. Meaning the ring caught on one of the ports and snapped the top of the piston off, causing all the rest of the damage. Usually a melted piston develops a hole in the top of the piston that looks literally like molten metal.
After watching the whole video it seems like you've potentially found the culprit.
I've found it's always good practice to start with fresh plugs and do a plug chop (while there's heat in the pipe go WOT & hit the kill switch then read the plugs) while tuning, starting with richer jets incrementally reducing jet size until the insulator on the plug is a nice golden/caramel brown color, I typically leave 2ts a little rich as a safety net incase an intake boot/gasket or crank seal decides to develop a leak that could cause a lean condition and it also help with cooling.
A lot of people don't do it but make sure when you clean the carbs to remove the needle jet from the carb, if there's any junk in between the needle jet and carb body it wont supply fuel properly.
It'd probably also be a good idea to run a colder plug than recommended from the factory for this use case.
I love the fact that the hovercraft is named Poop or Sh*t , the company named it well.
Two strokes are quite sensitive to exhaust tuning to get proper cylinder scavenging too, hacking off the exhaust might have had a hand in the failure as well, The water in the carb would definately lean it out too. I don't think the failure had anything to do with lack of lubrication and more to do with heat. Low octane fuel also burns hotter, and maybe check the heat range of the plugs too, might have been getting some detonation.
They are all different for sure. My EzGo two stroke is 128:1
It being a snowmobile engine previously Ill bet the motor came from somewhere high altitude and had small jets in it to deal with the thin air.
Bring it near sea level and boom too much air AKA lean.
low oil/fuel ratio like 50:1 is more likely going to cause bottom end issues not top.
I personally run 32:1-40:1 in my SCAT 1 because reliability and longevity are more important than performance for me, either way I wouldn't expect any issues 32:1 - 50:1
John and Ike,,,
Your on the right track with a problem with fueling..
It's not the ratio.
You probably have another problem contributing to this...
You can also read the top of the pistons to get an idea of fueling.
Quick Internet search will show you this!
Just remember 40:1 and 50:1 have been used on 2 strokes for a very long time!!
Don't think it's your mix that's causing you problems.
I think there should be some sort of skid plates on the ridges under the machine
Couple things to add to the very informative comments here, there was only one outer wear on one filter, will change the air fuel. And the other thing, water can run down your throttle cables and put water in the carb right down the needle. Jet fatter and stay heavy on oil. Plugs are much easier to clean and change while you lean it out a little bit. I've had 6 banshees and never blown one up with very heavy use by having big carbs and always jetted rich (carry spare plugs) also, use higher octane for the quality of fuel as much as octane. Have blown up 2 strokes but after I learned how to keep them alive I've had better luck than most, running 10 years on my current banshee and it is not babied. Maybe a little down on power but still a one kick machine. Have to pull it inside before it snows up here in minnesota! I also use nothing but amsoil for mix, have had very good luck with it.
Muriatic acid is what's used to eat away smeared aluminum on cylinders. Do that before honing.
What 2-stroke oil are you using? Get oil meant for aircooled snowmobiles. 2-stroke oils have different heatranges depending on engine type and if its a air- or watercooled engine. The wrong oil could be quite ineffective.