Reply To: Backfire/misfire thru carb

[Beno]

I also just realized that my 115hp bubbleback had those vents you mentioned at the top of the cylinder water jackets. This 140hp does not have them. Clearly the engine was designed to work without them.. should i drill and 1/8th inch tap them in or just let it go? My other boat is a 120hp straight4 mercury inboatd jetboat it has this style hole in its chrysler force block but its plugged off.