1. clean the filter on the fuel line, and the one in the inlet to the carb.
2. using a pump or airline, blow back up the fuel pipe into the tank and see if any crud comes out of the tank outlet, as this will let a little fuel through and when you open the throttle it will not draw enough and stall.
Or any of the following.
Possibly the whole carb is loose, linkages loose, air leak, governor linkage,
blocked jet - stalls and goes back to idle jet
float chamber float stuck.
Basically have a look at the carb, pop the bottom off, clean it and put it all back, you might need a gasket set.
JoeG, July 2012
