Small Engines (Lawn Mowers, etc.): Lawn mower wants to die after a few minutes of use., mechanical governor, float bowl

Question
Hello,
I have an annoying problem with my lawn mower. First off, it is a 5.5 hp B&S that is about 15 years old. It will start just fine, problem is after I have started cutting the grass for about 5 or 10 minutes, the mower engine will bog down and want to die. Sometimes it will die but most of the time it will rev back up if I stop forward motion. If it does die, it will start back up with no problems. Once I start forward motion again, it will bog down again after going a short distance. I stop and it comes back up to speed. As you can guess, this is very annoying. NOW, if I let the mower sit still on the dirveway, I can run the enigne at full throttle with no problems. I know this because this is how I drained the fuel tank in preporation for carb. removal. I removed the carb, and did a thorough cleaning of all of its parts. I cleand out all the ports and jets. Opened and cleaned the float bowl, and needle, and made sure all holes were cleand out by passing small wires through them.. Made a new gasket, ect..  I reassembled the carb and reinstalled. Gave it fresh gas still the same thing. What have I overlooked. My wife says just get a new mower. NO WAY. I like this mower and I will not let it defeat me.

Thanks for your help,

marsh91

Answer
Have you removed the engine blower/starter housing.  Many of the Briggs float bowl carb engines use a mechanical governor.  The lingake for the governor runs under the flywheel into the starter housing.  In the back corner of the starter housing is the governor arm.  This area is prone to catching dirt/debris and if enough stuff collects in this area it will prevent the governor from working correctly.

Remove the starter housing and clean this area.
Let me know what you find.
Eric