U.F.O
Mainemudder, They will work on 4 Strokes you just need the right carb, it wont work on my 4 stroke because it isn't a roundslide carb. But any 4 stroke with a roundslide carb it will work on.
I could swap carbs, but I am not going to for a $30.00 piece, not yet anyways.
Brambles