Check the screws holding the carburetor to the fuel tank are tight. Fuel seeping out under the carb means it is starved for fuel. I needed a new Diaphragm-Carburetor #795083. Place the membrane on the tank first then the gasket there are no directions with the part. Use starting fluid for one pull starts. I never use the primer bulb. Just remove the air filter screw and put the spray hose into the hole. Use the rim of the can to tighten the screw.

Sounds like a dirty carburetor. The surging would be caused by dirt or debris in the idle circuit. As it dies the governor opens the throttle which bypasses the idle circuit and the engine surges back to life. But in this case it sounds like the main jet is partially clogged as well so there isn't enough fuel coming into the carb with the throttle open either which causes the engine to die. A thorough cleaning of the carb should solve the problem.

I hope this helps!

-UtahAV
-Mark

Hi Dan,

Your particular engine is a Briggs L-head design. On the L-head engines the numbers will be stamped into the blower housing. (that is the housing around the flywheel that the starter attaches to. If your engine was an OHV design (OverHead Valve) then you could find the numbers stamped into the valve cover. The first number is the engine model number, the second is the type and the third is the code.

I hope this helps with your engine repair!

-Mark

Hi David,

It sounds like the engine is running rich. You may be able to solve the problem by adjusting the carb. Most likely it will need to be rebuilt or replaced. It looks like the carb for this engine is pretty reasonable priced. I think I would replace it. There are two different carburetors used depending on your engines serial number. The carb is item #90 on the parts breakdown.

I hope this helps with your repair!

-Mark

I have this exact same problem on the same engine on a 5 year old Yard Machine push mower. The motor surges but won't maintain top end speed. I took the old carb completely apart (not much to it, really) and rinsed it all out w/ carb cleaner. I put it back together and it worked for one weekend. Then I just tried it again today and it's back to its old habits. Once again, I cleaned the carb w/ carb cleaner and it seemed to work for about 10 minutes, then started surging again. I'm not sure if it's just the carb or the governor. The butterfly and governor lever keep going back and forth, like it can't find the sweetspot. Any ideas?

Like Mark posted above, the carb is a reasonably priced item, so it wouldn't hurt to just try replacing it, I guess. But I hope the governor isn't the problem. I'm not even sure how that part works.

RIck

Hi David,

Have you tried replacing the cylinder head gasket? If that's leaking then your cylinder would suck in extra air and would cause your carburetor to fluctuate and the motor to surge or run-rich.

Just a thought.

Hi Dave,

Good insight. A damaged cylinder head gasket could cause the engine to run poorly. It can also lead to dirt ingestion damage as the air going by bad gasket is not filtered. One correction, a bad gasket would actually cause the engine to run lean as more air would be added to the carburetor metered, air / fuel mixture.

Thanks!

-Mark