Small Engines (Lawn Mowers, etc.): B&S 19.5 - surging, craftsman riding mower, adjustment screws

Question
I have a Craftsman riding mower with a 19.5 hp B&S.  I've had this for about 8 years now.  The last 1.5 years it has had a bad "surge" issue...that mostly goes away at high RPM and when the mower blades are engaged.  I took off the carb 3 days ago, took it apart, cleaned it up, put it back on...same stuff.  I put in a new fuel filter, because it seemed like a lot of the gunk in the carb was from the fuel.  I have not cleaned out the fuel tank.  I noticed the vacuum hose leading to the fuel filter is slightly dry and cracked where it attaches to the engine (could that be part of the problem).  Anyway...anything that you can help with in narrowing the search.  I always like to start simple...so I have not even thought about anything outside of fuel and air issues right now.

Answer
Hello Mike:

This is Usually Caused by a Restricted Passage in the carburetor Idle Jet Port. By "Clean the Carburetor", Do you mean you Just Cleaned it with Spray Cleaner or Did you Soak the Carburetor Overnight in Carburetor Cleaner? If you Did Not Soak the Carburetor, then the Carburetor can Still be Dirty. I Suggest you Make Sure the Gas is Free Flowing to the Carburetor Inlet Port. If the Gas is Free Flowing to the Inlet Port, 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.*** (Do Not Use High Pressure Air for the Zama Carburetors, they have Check Valves for the Primer and these are Usually Blown Out of the Carburetor if Not Careful. Allow the Zama Carburetor to Set on a Drip Pan and Dry)***. Install New Parts if Required.** Replace the Cracked Vacuum Line and Us Screw Type Clamps Instead of the Spring Type Clamps. If by Chance you Removed/Loosened or the Governor Arm Slipped on the Governor Shaft when you Removed the Carburetor from the Engine. I Suggest you Also Reset the Governor.  If you Removed/Loosened or the the Governor Arm May have Slipper when Removing 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