QuestionI have a 19.5hp twin cylinder Briggs & Stratton mower. I just bought it and it starts up fine.
The problem is that the engine won't idle stably. It surges up and down. If I attempt to prevent the governor/throttle linkage from moving the rpms begin to pickup - but once I let go it drops off, revs up, drops off, ect. It is drivable and the problem presents itself the worst when there is little or no load (ie going down a hill). When going up an incline the problem completely goes away.
Any advice you have would be GREATLY appreciated. Thanks in advance.
Charlie
ps - my email address is charlieaf92 @ gmail.com (remove the spaces) - if you have any additional questions.
AnswerHello Charlie:
From your Description it Sounds like the Carburetor Requires Soaking and Cleaning. The Idle Air Port in the Carburetor is Restricted by Varnish Build up and Soaking in Carburetor is the ONLY Way to Completely Remove this Varnish. There are Some Other Possible Causes, but this is the Most Common. If you have Not Soaked and Cleaned the Carburetor, then **Remove, Disassemble and Soak the Carburetor Overnight in Carburetor Cleaner (I Use Gunk). I have Found that Most People can Use a Breakdown/IPL and Disassemble the Carburetor Enough for Proper Cleaning. You Only have to Remove the Bowl (if Applicable), Float Pin (if Applicable), Float (if Applicable) and Needle Valve and Any Adjustment Screws that Go Into the Carburetor Body. The Welch Plugs Do Not have to be Removed. Then Soak the Carburetor Body and Parts in a 1 Gallon Can of Gunk Carburetor Cleaner Overnight. The Can has a Parts Tray Inside it for the Small Parts. Once the Carburetor and Parts are in the Cleaner, you can Replace the Lid for Safety and to Prevent Accidental Spillage. Then Blow Out the Passages with Compressed Air. Install New Parts if Required.** The Other Possible Causes are: A Valve is Not Seating Correctly and Requires Reseating and Resetting. 2- A Valve Seat is Loose and Requires Replacing. 3- the Governor Requires Resetting. If the Carburetor has been Removed and the Governor Arm was Loosened/Removed from the Governor Shaft, then the Governor Requires Resetting. If you Removed the Governor Arm to Remove the Carburetor, then Reset the Governor. **To Reset the Governor; Loosen the Governor Arm Bolt and Turn the Governor Shaft Clockwise Until it Stops. Using the Governor Arm Hold the Carburetor to Full Throttle. Now with the Shaft Full Clockwise and the Governor Arm and Carburetor Held at Full Throttle, Tighten the Governor Arm Bolt. If the Engine Still Runs Full Throttle, then Reverse the Rotation of the Governor Shaft, but Still Hold the Carburetor at Full Throttle with the Governor Arm. If it Still Runs at Full Throttle, then Check the Internal Governor.** If you Hit a Snag or this Does Not Correct the Problem, I am Here if You Require More Assistance. Hope this Helps. Let me Know What Happens, Please. May the All Mighty Bless You and Yours. Thanks.
Good Luck
Respectfully
John
PS: I am Allowed to Answer 10 Questions a Day. If you See I am Maxxed Out, then Try Submitting your Question at or Just After 8pm EST (US). My New Day Starts then. Thanks.
Respectfully
John
