Possible rod knock?

[FirstTimeBoat]

Hey guys, wondering if I can get some ideas of what to look for. I recent bought a 1993 90hp yamaha. I had it on muffs and it seemed to have a little bit of lean sneezing when running. I clean up the carbs and took it to the lake to give it a run and see how it would go. When I got it into the water it took a bit to get started then when it did it had a knock at idle. When it was throttled up there was no knock and the motor ran good. Basically took it out just past the break wall and back in. The noise only seems to be there when idling in and out of gear. When I got the motor I was told the bottom end had 1800 worth of repairs for the shift shaft. Any ideas where I should focus my attention? I pulled the head off and opened the exhaust covers to inspect the pistons and cylinders. They look good. I also did a compression check at 110-115-110. I'm about to pull the powerhead for a disassembly, but would like some insight before I do.

 

[robert graham]

I believe some models of stainless steel props make a knocking sound at idle, but my 1999 Yamaha C90 has a stainless Ballistic prop and I'm not aware of any knocking sounds.... But 2 stroke outboards tend to make noises that are hard to identify....