I have an 05 Johnson 150 carbed motor and over the last year it has developed a clunking/banging noise coming from I believe the engine. I'll describe as best I can. First, I can't duplicate it. It is totally random. It only happens right after I put it in gear and am idling. I initially thought it was a spun prop but put another one on and same thing, sent my original one out to be checked and it came back no issue. Had the prop shaft replaced but it did it before and still after. Prop shaft was not bad, did it more for proactive measures. Does not happen out of the whole.

My thoughts are possibly the gears that engage when I put the motor in gear? No idea how that process works but it's a guess. Any idea's?