Briggs 11hp surges

[bruces]

Just bought an old used Encore 32 w/ 11 hp Briggs.

When it is running, the engine surges under load. It is like I am moving the throttle back and forth. The rpms go up and down, I can see the throttle linkage moving.

Ideas? I have changed the fuel, the air filter appears to be clean, am going to change the plug.

What else should I check?

Thanks.

[Robert Doubrava]

I would think you should check the governor linkage.:blob3:

[Bob Minney]

first thing I thought of too-governor linkage

[Tony Harrell]

Same here. I have a 12 hp that did that. I'd just fiddle with it and it would stop. It's sitting on the floor of my garage with a blown rod now. Better get someone who's QUALIFIED to work on it soon.

[khouse]

it could be too lean. have you tried backing the main jet needle out? loose linkage can cause problems also.

[grasmo]

too lean is about the only thing that will cause hunting. if it does it at idle and at wot i would check the intake gaskets or anything related in the intake runner part (cracks etc.). if it only does it at wot it has to be the main jet. it is in the middle of the float bowl and goes straight up to the venturi. take some carb or brake cleaner and spray it through the bottom. look in the venturi while you hold the throttle valve open and see if it comes out.