18hp FastTwin weird intermittent problem

[870 Expressmag]

When you say it starts to spit, are you sure it's running lean? It might be the float needle is leaking and causing it to flood at low speed; at higher RPMs it can keep up with the fuel entering the bowl.

That sounds reasonable, my thoughts on lean was due to the momentary rise in rpm before the spit, which usually when we have chainsaws with an rpm rise its a lean condition or air leak, however adjustment of the low speed idle had no effect on it, so it may be flooding, which might explain the smoking that I never had much of before