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Mend Briggs & Stratton 375 Lawn Mower Engine Throttle

My Briggs and Stratton 375 has two speeds - flat out or stop!?

I have a B & S 375 on a Masport mower. It's always performed well, but on starting it recently after a few months layoff, it seems to want to run at two speeds only. Flat out or stop! When I start the engine, it immediately jumps to high revs, but throttling back simply causes the engine to cut out. No amount of juggling the throttle will produces a comfortable level of intermediate revs. I've lubricated the throttle cable to ensure it operates smoothly (it was a bit 'sticky' before) but the problem is still there. Does anybody have any suggestions?

Grant
July 2009

Briggs & Stratton Briggs & Stratton 375 Garden Tools, Lawn Mowers Lawn Mower Engine Throttle

You were right on the money, Phil. I removed the air filter and the pull rope assembly and discovered enough dead grass around the governor mechanism to start a bush fire. I cleaned it all out and it's now ticking over like a well oiled sewing machine. Many thanks, you've saved me a heap at the local mower shop where they would have found a lot more things wrong!!

Grant
July 2009

Thanks for that, Phil I'll have a look and see if anything's clogging up the works. Possibly some dry grass.

Grant
July 2009

The govenor linkage is stuck. Remove the air filter and check that the springs are not twisted/caught up, and that nothing is physically jammed. There are only 10 grams (at best) of force available to move the throttle butterfly, so it has to be FREE.

phil_saunders(a)bigfoot.com

Phil Saunders
July 2009