Geoff 93 RRC wrote:

:Try a colder heat range plug. Are they the correct ones for the marine
:motor? The carburator probably needs rejetting otherwise - just take it off
:and take it to a carb shop.

Thanks. I'm using NGK BP7HS plugs now, which is what NGK says is
correct for my engine (Volvo AQ130C I/O). I'll try a set of NGK BP8HS
and see if they help.