Working on my sons 1993 250 4x4 2 stroke. I cannot get it to turn over. It appears to be spitting fuel out the back (carb side) of the engine. Should that be sealed? Any thoughts on that it could be? It just won't fire...

 

Could just be carb related (worn needle and seat,float level off) causing too much fuel or if compression is too low it will do the same thing,spit gas out the back of the carb.I'd do a compression test before you do anything else.

 

Thank you! Will try to get to that asap.

 

OK compression test done. 90 psi was all I got... What's my next best step? Thank you!!

 

Took the carb off just now. All looks good and clean. Took the bottom plate and all looked good. That wouldn't affect compression at all would it? The fuel is still coming out the back between the carb and the engine... thanks for any advice!

 

To begin with 90 psi is too low. That could be part of the reason fuel is spitting back as it can't compress the fuel/air mixture and ignite.Plus hard to tell wear on a carb needle and seat by just looking at it.It still may need a carb kit before you're through. Another thing besides having a new over size piston and the cylinder bored, is worn crank seals that most people over look. If they're leaking the fuel/air mixture can't compress and shoot up the transfer ports for ignition.The one behind the drive clutch causes the most problems.Cheap parts but critical. Same thing for top end compression.Polaris Trail Boss 250, 1985-1999, Engine Crank Seals

 

Thanks! Going to build a leak test kit first... Here is a nice video I found, seems fairly easy.

 

You can build a leak down tester if you wish,but about as easy to just pull the drive clutch and stator,replace the seals and be done with it.

 

Understood. Will do that first... Thanks!

 

Ok got the clutch off. What's the best puller to get the flywheel off? Not having any luck with a gear puller. I think I've screwed up the crank threads... any tips?