detonation / knock issue on 340

shimsham1 said
engine runs extremely cool, wont go above 190 no matter what. I have not tried messing with the fuel mixture yet and will do that this weekend.

Start with the easy stuff first as others have said.
When you pull the spark plugs to run your compression test take some closeup pic's of the plugs and post them here. They will tell you a lot - A/F ratio, timing etc