My .63 has had a reduction in performance lately. To the point where it barely runs at all now. (I have been running this engine almost every weekend for about 2 1/2 years.) It will start fine, but starts to bog down and quits after a few seconds of running. I have tried fresh fuel, new #8 plug, new fuel tank, and of course, adjusting the needle. I removed the regulator diaphragm and it has a substantial ring pressed into it from the plunger, but no noticeable holes. Could this cause my problems? What about air leaks in a gasket somewhere? What about the plunger and spring? This is (was) a great running engine, hope I can fix it with out sending it off. Thanks for your help, David.

I was told not to use a no.8 in my 140, maybe that is the problem? I dunno if it could be the same with the 63. I would try an OS F.

OH SHOOT! I ment to say letter F plug. Thanks Robert!