[Coffman05]

I just purchased a non running 93 Polaris trailboss 350 for a project. Dont know alot about these engines so I'll be doing alot of learning. I pulled the starter/flywheel cover off and there was what looks like oil in the bottom of it. Not sure if it was just moisture from sitting that got dirty from inside the cover or if there is supposed to be oil in there. Any ideas. Thanks

 

[FPD218]

Welcome to the forum

Your question has now been logged into the queue and the next available forum member latebird will answer you shortly

 

[latebird]

The 350L just like the 400L is a two stroke engine and the crankcase is pressurized during the power stroke to transfer fuel/air to the combustion chamber. The pressure combined with the rotation of the crankshaft may allow some fuel/air to migrate past the seal. It is not abnormal as long as it is only a small amount. As the engine and parts age and wear, the leakage increases. At some point the engine needs a complete rebuild to remove play from the crank main bearings and minimize the leakage. If you have the engine pressure tested, it should hold 7 PSI for 7 minutes - longer is better - and 10 PSI could push the seals out of the engine - if it is pressurized to 7 PSI and loses more than 1 PSI per minute, it need to be rebuilt to restore performance and power.

 

[Coffman05]

Alright I'll check that out. I haven't had it running yet and the cover wasnt even on it when I bought it I just seen a little oil underneath the flywheel and in the cover. It was just a small amount but I'll keep an eye on it once I get it running