I should first mention I am actually a mechanic but I have never messed with this engine. I was brought in because it seemed rather odd.

Engine would start a low rpm and want a lot of choke for whatever reason. Engine sounds normal, if you give some throttle, it would then start a VERY obvious rattle or top end knock.

It was very strange because the noise would seem to come and go and I simply could not detect the source of the noise in the 2-3min we ran it. While at near idle and still rattling, she locked up. No doubt I will now find the problem but I am really unsure where to start. starter sounded normal so not really suspecting the start clutch. Almost like a valve was hanging up but this is a pretty aggressive clank than valve tap.

I have not heard rod knock that would come and go and if I had to explain the noise I would say the sound of a screwdriver tapping on a metal heat shield.

No smoke, low on oil. no oil light when running, not suspecting CVT clutch issues. Seems to be on front side of front cylinder.