Small Engines (Lawn Mowers, etc.): 2003 craftsman 20 hp, briggs and stratton, head gasket

Question
QUESTION: hello john, i have a 2003 craftsman 20 hp mower with a 42 inch riding deck. the motor is a briggs and stratton with ohv. it seems that the left spark plug is not getting fire because it seems to be wet when i remove it, while the right one is burning white. this only shows to miss when i engage the mower. is this a coil issue and do these have a double coil on them? thanks for the help,danny

ANSWER: Hello Danny:

Depending on the Engine Model it May be a double Coil Engine or a Single Coil Engine. Usually if it is a Single Coil Dual Lead, Both Plugs Stop Firing. I have Seen a Few Cases where Only 1 Plug Fired and the Other Did Not on the Dual Lead Coils. Send me the Model Numbers Off the Engine, Please. With these I can Locate the Proper Manual and Better Assist you. Leave the Plug Out of the Cylinder that Is Not Firing and Hook it to the Coil Lead. Wrap a Wire Around the Threads of the Plug and Attach the Other End of the Wire to the Engine Block for Ground. Turn the Engine and Watch the Plug. If the Plug is Firing, then the Coil is Good and the Problem is a Bad Intake Gasket, Crack in the Intake on the Side Leading to the Dead Cylinder or a Valve Problem. Check the Valve Clearance. Intake .003in - .005in and Exhaust .008in - .010in. Brigs Suggest .004in and .004in.,  but I have Less Burnt Valves and Easier Starting with the Other Settings. Hope this Helps. I am Here if You Require More Assistance. Let me Know What Happens, Please. Thanks.

Good Luck

Respectfully

John

---------- FOLLOW-UP ----------

QUESTION: the numbers i found were 4076770229 e1,020725yg00234,family: ybsxs.7242vf.  the mower model number is 917.272911. thanks dasnny

Answer
Hello Again Danny:

This Engine has 2 Coils/Magnetos. Did you Check the Coil by Wrapping a Wire Around the Threads of a Plug as I Described Earlier? The Coil May be Bad. The Valves May Require Adjusting. The Cylinder May have a Head Gasket Blown Between the Cylinder and the Valve Stems. 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 (407677-0229). 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