Briggs 12H802-2682-01 surges and surges...

[dart451]

Wonder if anyone might have some ideas about this Briggs motor. It's on a Sears Tiller...was sitting for several years. Got it running but it surges all the time. I thought it might be the carburetor so I put a new one on, same surging. I also changed spark plugs, checked gaps, no difference. I have not checked the governor yet seeing as it's under the cowling but I find it hard to believe that that would have changed.. Anything else you guys would look at??

[toro-8-2-4]

Check for air intake leaks. Make sure the gaskets are fine and are aligned correctly so that no air may be leaking in.
Sometimes on the cheap Chinease carbs the main jet needs to be opened a few thousandths to get it run richer and stop the surging. Non adjustable carb I assume? You can try swapping out the jet from the old carb and see what happens.

But check the governor and everything else before you modify the main jet. ONly do that when everything else checks out.

[hanz63]

The few of the cheap carbs I've seen on these that were bad from new had a drive in brass seat that was not set all the way, hence a low float level.

[KE4AVB]

First the 12H802-2682-01 is more likely 12H802-2682-B1

Second this engine comes setup with three different carburetor configurations. Primer, Choke, and Auto-Choke. All three uses different main jets so you need to setup you have and order the correct carburetor or main jet then if it is still surging check that governor static is set right and then look for air leaks. IF none of these are out of order than resizing the main jet may need to be done provide if partial choking of the intake removes the surging.

[RoyM]

Hold yur finger on the throttle shaft. If it smooths out the governor is too sensitive and needs to be adjusted. If it stumbles and dies it is a carburetor or leak problem.

[dart451]

First the 12H802-2682-01 is more likely 12H802-2682-B1

Second this engine comes setup with three different carburetor configurations. Primer, Choke, and Auto-Choke. All three uses different main jets so you need to setup you have and order the correct carburetor or main jet then if it is still surging check that governor static is set right and then look for air leaks. IF none of these are out of order than resizing the main jet may need to be done provide if partial choking of the intake removes the surging.

I guess I should choke it abit while running, see if it runs smooth...