Just bought a 250 trailboss
it would run for about 10 minutes and then shut off and gas was running out of the carb - we put a new float valve in and it quit leaking - it started fine - and quit leaking - after another ride for about 10 minutes engine quit - we tried putting gas in carb - and it will not start. We have spark - we have compression - gas is new - oil is full - we cleaned the rest of the carb - cleaned the vent tube to the gas tank - it still will not start. I do not know how much pressure we have but it is pretty easy to pull over so I might start there - any other thoughts??????? I am not the one working on it my dad is - but I want it running and can type pretty good......please help

 

Compression must be around 115-120 psi to run right. Plus even if compression is this much,could be a leaking crank seal that can keep one from starting. In other words,it must have good top end compression and crank case compression/pressure must hold for the gas/oil/air mixture to atomize properly and shoot up the transfer port for ignition.

 

Thank you very much - I will have him check the pressure - and I will post back.