hungyzerglin
New member
This motor was originally purchased by my parents in 2000, they used it for 2 years before it sat in storage for a long time. I took it out recently and tried to fire it up with some fresh 50:1 mix, but it wouldn't start. Compression test showed low compression, about 40-50 PSI. Took the powerhead apart, found the piston ring was stuck in the groove, broke it trying to take it out and replaced it with a new OEM one (made sure it could move freely). Piston itself and cylinder walls looked to be in good condition, as well as the intake reed valve, so I did not replace those. Replaced the crankshaft oil seals, cylinder head gasket, drive shaft housing gasket and spark plug. After all this, I still only get around 50 psi, and when I spin the flywheel with a drill the motor almost wants to fire when I have the carb 3/4 full choke. Seems like somewhere compression is leaking but I'm stumped. I bought a cylinder leak down testing tool, and when the piston is TDC it holds pressure. Any help or suggestions on where to look next would be appreciated. At this point I'm wondering if the cylinder walls are out of spec or I need a new piston (isn't just the piston ring doing the real sealing work against the walls using a film of oil)?