[Zeke]

I've had several small engines develop that syndrome. It always boiled down to dirt in the jets.

I remember a time when I had the kart out at the track. I'd get a half a lap and the thing would not run. I came in, fiddled around, started it and it would go like hell for.... a half a lap.

Finally, I tore it down far enough to find Dalmatian dog hair (very short little spikes) in a passage. What had happened is that the funnel I used had the dog hair in it. With the little bit of oil used on 2-cycles, the funnel was just sticky enough to hold to hairs.

They got thru to the innards. About 3 of them.