B & S 9L602-0927 governor issues

[MomsMustang]

Replaced the carburetor because it broke where the primer bulb is. Also installed the new spark plug and air filter that came with the carburetor. Replaced the governor spring since it looked stretched out. The mower starts but the speed varies constantly. I can see the lover on the throttle shaft moving back and forth. Is something broken or out of adjustment? I did clean the area where the governor lever attaches to the vane.

 

[Hexxus]

I think I am having this exact issue. Hopefully someone helps us.

lawnmowerforum.com/showthread.php/47857-Push-mower-surging-idle?p=295071#post295071

 

[bertsmobile1]

it is called surging and has nothing to do with the governor spring.
Surging happens when there is not enough fuel to maintain full speed.
Two causes.
1) not enough fuel
2) too much air.

Those carbs fit on a long plastic tube which will often crack or split when you remove & replace the carb.
Then there is the O ring which goes hard over time so while it is tight, will not make an airtight seal.

Finally there is the diaphragm & pump under the carb.
The diaphragm must go directly against the tank then the gasket between the diaphragm & carb.
These are much easier to do if you turn the cab over then place the gasket & diaphragm on the carb then drop the tank on top of the lot.
hold then tight together flip it over then pop in the screws & tighten them criss cross and all the same amount.

Usually you can hold one or two screws in the upturned carb to position the gasket & diaphragm to get everything into position and don't forget the spring.