Don,


50 flights is only a bit over 10 hours.
This is not sufficient time for your engine to have worn-out, i.e. to need a new ring.

With a four-stroke engine, even if you try running it lean, it will stop and possibly even back-fire and throw the prop.


Do check the valve-lash, like Dave wrote. This must be done with the cam-follower on the base-circle, i.e. at zero lift.


As a rule, compression is always checked only with the throttle wide-open, as Jim wrote.