Little trick to help save piston burn downs

[leech~~]

It seems like most piston burn downs happen late in the season when the weather is getting warm and when making long runs across lakes with heavy wet snow. I learned a little trick that I use when running late season lakes that I got from a NASCAR driver actually.

When making long high speed runs across a lake keep cracking your throttle or adding extra Rev's in bursts. Since the gas in your tank is pretty cold, this shoots little shots of cooling gas into the head and on to the piston which helps cool it a bit and may help keep the piston from burning down during a long run.

This is just a suggestion that may help, of course there are a lot of reasons pistons burn down. I got it!

Give it a "shot".

[shortfatguy]

Burping the throttle is a good practice anytime of the year. Many snowmobiles have lean spots in the rpm range. Holding the throttle steady in one speed can lead to a lean burn down. Burping the throttle after a wide open run will also help by cooling as you stated. The main reason for piston failure I see is poor fuel. Either low octane causing detonation or water in the fuel freezing in the carb and leaning out one side. I really think running regular premium fuel instead of non oxygenated helps stop this issue. The ethanol in the regular fuel absorbs water and allows it to be burned. I laugh when I see people pay extra for non oxygenated fuel and then dump a bottle of heat into the tank.

[clKiekhafer]

Burping the throttle is a good practice anytime of the year. Many snowmobiles have lean spots in the rpm range. Holding the throttle steady in one speed can lead to a lean burn down. Burping the throttle after a wide open run will also help by cooling as you stated. The main reason for piston failure I see is poor fuel. Either low octane causing detonation or water in the fuel freezing in the carb and leaning out one side. I really think running regular premium fuel instead of non oxygenated helps stop this issue. The ethanol in the regular fuel absorbs water and allows it to be burned. I laugh when I see people pay extra for non oxygenated fuel and then dump a bottle of heat into the tank.

Did you ever think that the ratio of dumping heat (12 oz bottle) into 10 gallon of gas is about 1/10th the ratio compared to 10% ethanol? In other words, adding heat is 0.1% alcohol compared to 10% ethanol. I know heat is different than ethanol, but you were comparing the two not me.

[shortfatguy]

I have never Had an issue running the ethanol fuel in any sled I own. The only issue I could see is long term storage. I would rather use 91 with ethanol than nonoxygenated with water in it. Unless you are getting your fuel from a place that goes through a lot of nonox I would bet the fuel is questionable. I rebuild around 50 snowmobiles a year and have yet to see a failure due to ethanol in fuel. I have however seen plenty of failures due to nonox with water in it.