Frank, I’m trying to remember if the QD10 has a MD carb? When I worked on them many years back, I had more problems with the Primer Plunger O-Ring seal, and they are expensive as I recall? I was getting just too much air leaking by, and when it was changed, all was ok. My old notes show part # 302000, and upgraded to 375935 for this fat dia. o-ring. Just trying to point out to Billy to look here also.