G'day MF,
Nah, the actual wasps had departed. It was really obvious, to anyone with any experience with small engine repairs. When I say that it was blocked solid, it really was chockers with mud - right up to the muffler outlet!
I have a Honda GXV120 engine here, that has the same problem, that was on a SupaSwift Big Bob mower I got for $20, as a chassis parts donor.
Don't think I'll bother resurrecting that one, though.