Small Engines (Lawn Mowers, etc.): High Compression (Auto Decompression ?), twin cylinder engines, briggs stratton

Question
Hi I have a ride on mower it has done only 40 hrs total even though it is a 1999 model.It is a Briggs & Stratton 17hp model 311777  Type 0133EI  Code 98031020 It is having trouble turning over the motor as though it has too much Compression,sometimes it spins over fine and starts and runs great but now it turns too slow to fire up it gets over its compression stroke only to stop until tried again,There is a new Battery as well as I've put jumper leads from the car same problem too much comp,taken out plug spins fast no problem,the valves have not been touched and i was wondering does this engine have a auto decompression like my 4 stroke motorcycle if so could this be the problem ,I've looked through the manual but cant see anything that looks like one .This Engine is in exceptional condition  not much work.The last time i tried again the solenoid does seem to work so i power the starter direct still just turns over the same,Hope you can help Regards Gary

Answer
Hello Gary:

Sorry for the Delay. This Question was Located in the Question Pool and I can Only Answer Questions from the Question Pool when I am Not Answering Questions here or at the Other Site I Answer Questions at. Also, I am on Vacation and had a Few Minutes to Answer Questions. From your Description it Sounds like the Valve Clearances Require Resetting. You can View a Breakdown/IPL of the Engine at this Site Addy; http://www.briggsandstratton.com/maint_repair/manual_and_more/doclist.aspx?categ... and Enter the Model Numbers (311777 ) and the First 4 Type Numbers (0133) in the Appropriate Boxes and Click GO. Then Select Download PDF. 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. 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