QuestionI have a 4 year old Sears 21" mulching push mower with 5.5 HP Briggs & Straton engine. I've changed the plug, air filter, and oil each year.
Last year the engine power began surging after each start up (alternates between high and low power approximately 2x a second), and this season's first cut this problem continues. Left idling and standing still, the power surging slows then stops, but then starts again when the mower is moved. Taking the cover off and running the mower I can see what I assume is the throttle (a small lever attached to a spring and small cable) shifting back and forth. I can hold this lever still and the engine does stop surging, but when I let it go the surging will start again when the mower is moved.
Any thoughts on what the problem is? Is this a serious problem? Solutions? Thanks in advance for helping.
AnswerMost all surging problems are carburetor related.
To start, I would drain the gas. Next, remove the carburetor float bowl nut located on the bottom of the carburetor. Have a rag or container to catch the gas that drains out of the carburetor.
Replace nut being careful not to over tighted the soft, brass bowl nut.
Re-fill with gas and see how it runs. If it still surges, more than likely you will need to remove, disassemble and clean the carburetor with compressed air and carburetor cleaner. This normally fixes the problem.
Let me know what happens.
Eric
