my 1998 mercury 225 efi developed a knock while cruising around half throttle the other day. pulled all the plugs and found one that looked like this. weighing rebuild vs new powerhead vs rebuilt powerhead. I am pretty solid with a wrench as i do it for a living but just not boats. anybody have an idea what a new power head will cost me? also what should i be looking for when i take this powerhead off as a source of failure im thinking an injector clogged but not 100% sure if what on the plug is aluminum or carbon
i could not find the serial number on the motor but did find this part number on the power head 37855211