I have a Toro 6.5 hp Tecumser. The primer bulb did not seem to do much so primed it by hand and it would eventually start, run for a minute and quit. Do this a few times and it eventually stayed running. I read about cleaning the carburetor bolt so did that with no luck. The fuel is new ,clean filter, and good gas flow into carb. Finally bought a new carburetor and exactly the same???