Small Engines (Lawn Mowers, etc.): 20 HP Briggs Intek, blown head gasket, twin cylinder engines

Question
I have a 20HP Briggs Intek on my Craftsman Garden tractor. I starts fine but I constantly have to play with the choke while runnung to keep it smooth. Any advice? Briggs engine #407777-0122-E1

Answer
Hello Jeff:

A Few Causes Jump to Mind. The Valve Adjustments, the Carburetor and a Blown Head Gasket. Check the Compression. If the Compression is Good, then Start with the Valve Clearance. 1-  I Do Not Use the Setting Called for by the OEMs. I have Found that the Following Works Best. Remove the Valve Cover (on the Dead/Weak Cylinder for Twin Cylinder Engines). Now Loosen the Valve Adjuster Locks and Set the Intake Valve Clearance to .004in -.006in and the Exhaust to .008in - .010in. I have had Better Performance Out of the Mowers and Less Burnt Valves Using these Settings. 2- Remove, Disassemble and Soak 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, Float Pin, Float 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 Accidential Spillage. Then Blow Out the Passages with Compressed Air. Install New Parts if Required. 3- If the Compression is Bad, then Check for a Bad Head Gasket. You can View a Breakdown/IPL of this Engine at this Site Addy, http://www.smallenginepartswarehouse.com/parts.asp and Select the Shop Online Parts Look Up. Then Select the Model Tab. Then Select the OEM and Enter the Model Numbers. Then Double Click on the Model in the Results Area. Now you can Select the Section of the Engine you Wish to View. Hope this Helps. I am Here if You Require More Assistance. Let me Know What Happens, Please. Thanks.

Good Luck

Respectfully

John