Small Engines (Lawn Mowers, etc.): B&S 6hp engine throttle issues, briggs stratton, ring gasket

Question
Ben,

How is it going?

I have a Briggs & Stratton 6 HP mower.  Model 12H802 Type 3180-B1 CODE 01032759.  It has been in storage for about a 1 1/2 years.  At first it would start and run for about 2 seconds then stop.  So I took the carburetor apart and cleaned  several times.  I replaced the gaskets, changed the oil, changed the spark plug, and changed the primer bulb.  There is no fuel filter that I could find, only a small screen between the primer bulb and carburetor, it looks clean.  NOW the engine starts, but does not really idle, it revs high then low almost stalling. I would appreciate any suggestions.

Thanks
Mike

Answer
Mike
Sounds like you have a surge problem.

Problem: Engine idles roughly, unevenly, or surges.
Possible causes:

Carburetor is dirty.
Air leak in carburetor or intake manifold (e.g., bad O-ring, gasket, primer).
Carburetor is improperly adjusted or needs service.

Fuel line or fuel tank cap vent is clogged.
There is water in the fuel.
Fuel pump is defective.
Governor is not set properly, sticking, or binding.
Carburetor needs adjustment or service.
Loose carburetor/intake pipe resulting in vacuum leak.