Hi Bob,

Thanks, However I am totally pissed...I spent the whole day on the engine and still can't find the problem. I did everything you said and triple checked everything!! The carb primary inlet screen is clean... I also checked the piston by the exhaust window and its like brand new. The engine start fine and pull strong at high rev..However when I pull back to idle the engine run a few second, start to rev and die...I changed the plug, fuel lines, removed filter, new tank with new clunk etc......

The only thing I can see is not enough back pressure from the muffler at idle...

Oh well...

Serge