Got an OS48 surpass, aquired from my father (passed away).

It looks new and started easy, but then sounded like a thrown prop.

Symptoms - As each cam follower passes over the dwell there is a loud click. Replaced the followers but this has not cured. Cam looks fine - no scoring.

ANY IDEARS

The clicking is normal. The cams are high-lift, and the followers make a click as the come off the cam. They basically fall off the cam onto the non-lift part.

But if should not sound like a bag of nails, when running ?

Cliff

If the engine is making a lot of noise when running, then it's likely the bearings are shot. Four-stroke engines can get corroded bearings in a remarkably short time.