Used OS 91 FX engine doesn't offer much resistance when I flip the prop
with my finger (the engine is not set to run, of course). There seems to be
very little compression. Is this common with this engine or does it appear
that I need to replace the piston ring - maybe the ring and also the piston?
I don't know the run hours on the engine. Any ideas? Many thanks,
Ollie 707-538-1855 Santa Rosa, CA.