I accidentally broke the governor spring installing the carb . About a half inch broke off at the end due to corrosion. I reinstalled it and ran the motor but it came off while running and I shut it down right away because it sounded terrible. I reinstalled again and was mowing the lawn when it starts to surge in and out while moving with the deck engaged. I get a new spring and install it hoping this is the fix but I still get that surge but not as bad as before. With the deck disengaged the engine runs nice and flat without surging. Is there any adjustment to the governor?Did I damage something when it ran without the spring? I see that it's a vertical slide type but don't have a clue how to adjust it. I even bought the engine manual and it doesn't explain it either. It's a B&S 12hp M281707-0411 Vertical shaft with a one piece flo jet carb.

Sounds like the carburetor is set a little too lean on the high speed or load circuit. There is an adjustment screw on the bottom of the bowl nut on your carburetor. Open the screw up 1/8 to 1/4 of a turn and see if it helps any.

You should not have had any problem with the governor spring when you removed or reinstalled this carburetor. If you are talking about the long spring that runs from the governor arm to the throttle shaft, this spring just keeps tension on the connecting linkage to prevent play in the linkage from affecting the engine rpm's. The actual governor spring is located behind the plate that the throttle cable attaches to and is attached to the governor arm about midway up.

Thanks for clarifying the governor spring issue. The diagram I have shows only the throttle linkage spring. I tried your suggestion with the bowl nut but no luck. My neighbor the so called know it all type says any time you take the carb off you should readjust the governor. Is this possibly the problem? I'm not trying to second guess you I'm just not that adept on small engine repair.

It's always a good idea, but I find that it's rarely ever needed unless you really stress the linkages when removing or reinstalling the carburetor.

I literally remove over a hundreds carburetors a season for service, and I have to adjust less than 1% of the governors.

This does not mean that yours does not need to be adjusted however.

Generally though if the governor is the cause of your engine surging it would actually be more noticeable with no load then with a load.

To adjust the governor you will need to loosen the governor arm on the shaft that is coming out of the engine block.

Once the arm is loose apply pressure to the arm in the direction that places the the carburetor in a wide open throttle position (WOT).

While holding the arm in this position, rotate the governor shaft in the same direction it would turn to produce the WOT for the carburetor (the end of the governor shaft is usually slotted and you can use a screw driver to rotate it.) Turn the shaft until it stops.

While holding the the governor arm and shaft in this position WOT, (with your third hand) tighten the retaining screw back down on the governor arm. Your governor is adjusted.

If your engine races when started, then you did not get the governor adjusted properly. Immediately shut down the engine and repeat the adjustment procedure on the governor.

Thank you very much. I'll try that after I grow a third hand.

How do I know what direction the governor shaft turns at WOT?

Look at the direction the arm moves to bring the throttle to WOT, then turn the shaft in the same direction. I don't remember which direction this is for your engine without looking it up, but if you look at the throttle shaft you can tell which way it has to turn to open the throttle when you move the governor arm.