I rebuilt the motor fresh over the winter, and taken her on quite quite a few trips since.
All of a sudden when I go to start it, it revvs highly at startup even though carb is closed.
I suspect there is an air leak somewhere on the case, causing it to be able to suck air and rev up lean (it did not run for more than a second or so)... Does this sounds like a reasonable guess? I havent been able to tear into it yet, I just want to have a good idea of where to look first.