Small Engines (Lawn Mowers, etc.): valve settings or some idea of my problem?, blown head gasket, twin cylinder engines

Question
I have a 4 year old briggs-stratton 17.5hp 31c777 model and i am at my witts end. i started with a blown head gasket. i replace it quite easily and it sounds the same as before pooping loudly thru the carburator. i think i have not adjusted the valves correctly. my local shop told me the correct valve settings on both valves was .004. the engine starts easy but runs rough and no power and all the neighbors know when i am working on it. this is a matter of being stubborn and trying to complete this repair myself. if you can give me some assistance i would greatly appreciate your knowledge and give me a shovel in the right direction.

Answer
Hello Nate:

The Following is a Basic File I made for Setting the Valve Clearances. Any Input is Appreciated. **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 Cylinder for Twin Cylinder Engines). Set the Cylinder you are Setting the Valves on to Top Dead Center on the Compression Stroke When Setting the Valve Clearance. Now Loosen the Valve Adjuster Locks and Set the Intake Valve Clearance to .004in -.006in and the Exhaust to .006in - .008in. I have had Better Performance Out of the Mowers and Less Burnt Valves Using these Settings. Be Sure the Piston is at TDC on the Compression Stroke.** On Some Engines you can Us a Straightened Coat Hanger and Feel the Piston. Be Careful and Dont Jam the Wire in the Cylinder. Usually the Piston will Push the Wire Out of the Spark Plug Hole with No Problems. Did you Check the Valves for a Burnt Valve Seat when you Replaced the Head Gasket? If No and the Valve Clearances that are in the Instruction File Do Not Correct the Problem, then Remove the Cylinder Head and then Remove the Valves from the Head and Inspect the Valve Seat Face and the Valve Itself for Burning. Reseat the Valves and then Assemble the Engine and it Should Run Correctly. You can View a Breakdown/IPL of this Engine at this Site Addy, http://www.outdoordistributors.com/ and Select the B. Then Select Briggs and Stratton. Then Select Don't have Part Numbers. Then Select the File # 31. Then Select the Folder # 31C700. 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