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Briggs & Stratton Quantum XM 4.5 hp

Jakester's Avatar

Join Date: Aug 2007
Posts: 1

09-06-07, 08:27 PM   #1  
Briggs & Stratton Quantum XM 4.5 hp

I am having trouble with this motor starting and idling.
It only starts with 3 good pumps of the primer button, puffs blue smoke once, and runs. This is a minor problem.
Once running, it doesn't hit full idle speed but surges up and down. If I physically hold the external component of the throttle plate, it runs smoothly at higher RPMs. I notice there is a spring and small rod connected to either end of the external component of the throttle plate. How can I get it to run smooth? Is it the spring, or is there a vacuum/inertia component that needs fixing?



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cheese's Avatar
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Join Date: Jul 2001
Posts: 16,569

09-06-07, 09:18 PM   #2  
Sounds to me like you need to clean out the carburetor. Remove the carburetor bowl screw and note the tiny holes in it. Clean these out as well.

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