No i never foul a plug. you have to be carefull when compairing jets as there are many places to richen an lean out on this carb you can go goofy trying to make a best setup for the day. way to many variables. we could talk slides an nozzels an really get you confused. lol. also icc engines are not the same a pavesi uses less fuel than a tm, an a modena use a tad more fuel than the tm so best to do your homework.