Small Engines (Lawn Mowers, etc.): engine wont run under load, throttle plate, speed circuit

Question
I have a Poulan tiller with a 5hp B&S engine Model 130202 Type 1906-01. Just recently the engine kills as soon as it gets under a heavy load. It seems to be worse as the engine gets hotter. It starts back up after about 2 pulls, but then dies again as soon as I start to till.

Answer
How old is the tiller?  If it idles and runs fine without a load then the low speed carb circuit is probably not the issue.  Under load, the governor opens the carb throttle plate and the carb high speed circuit takes over.  I would start by removing and dis-assembling the carburetor.  Use compressed air from an air compressor to blow out all the carburetor orfices (holes) and spray carb cleaner through everything the make sure the carb is clean.

Let me know if cleaning the carbs solves the problem.

Eric