I will disassemble the engine and check the bearings/sleeve.

navav2002, I set the pipe is set fairly conservatively, so the needle setting is pretty broad and not "peaky".

airbusdrvr, I have used the "F" plugs.

I am pretty obsessive about checking the mixture and am almost certain that the engine is not running lean. The plug is not giving the usual evidence of a lean run.

I hope to give an update later today.