Small Engines (Lawn Mowers, etc.): engine trouble, briggs straton engine, jumper wire

Question
Hi I have a murray rear engine riding lawn mower with a 12 horse power Briggs&Straton engine that wont start. Engine Info Model# 283707  type # 0139 01 turns over fine, gas wont ignite (spark plug not the problem)What should I do? What should I check?

Answer
Hello Collin:

>>From your Description it Sounds like a Bad Safety Switch or Connection to a Safety Switch.
>>The Following is an Instruction File for the Safety Switch System. Any Input is Appreciated.
>>The Color Code of the Wires May be Different than those I Use as a Reference in the Instruction File.
>>**PLEASE REMEMBER THAT THE INSTRUCTIONS FOR CHECKING THE SAFETY SWITCHES IS JUST THAT!!! FOR CHECKING ONLY.
>>I NEVER Suggest a Mower be Operated with a Safety Device or Switch Disconnected or Bypassed.
>>**Now. On Some Model Mowers you can Simply Unplug the Safety Switch from the Harness. On Other Models you have to Place a Jumper Wire Between the Harness Terminals (on the 4 Post Switch (Clutch/Brake) Jumper from Same Color Wire (Example: White to White) First and then Check for Fire, Now Include the Black to Black Wires if No Fire. Check the Clutch/Brake and the Blade/PTO Safety Switches First.  Then Check the Oil Guard Switch (if Applicable). Check the Seat Safety Last. Usually the Seat Safety is Not in the System for Starting the Engine. Just to Ensure Someone is in the Seat when Engaging the Transaxle and/or Blades. Use a Paper Clip or a Short Wire to Make a Jumper.**  
>>Use a Multimeter and Check the Continuity of the Switch. The Meter should Show when the Contacts are Closed and Open. The Meter will Swing All the Way Over when the Switch Contacts are Closed and Swing Back to the Rest Point when the Switch Contacts are Open.
>>Is the Plug Firing? If Yes, then
>>Check the Valve Clearances. They may Require Setting.
>>You can Locate the Correct Specification for this Engine at this Site Addy; http://outdoorpowerinfo.com/engine_specs/ and Select your Engines OEM and the Specification Chart you Require.
>>You can View a Breakdown/IPL of the Engine at this Site Addy; http://www.briggsandstratton.com/maint_repair/manual_and_more/ and Enter the Model Numbers (XXXXXX) and the Type Numbers (XXXX-XX) in the Appropriate Boxes and Click GO. Then Select Download PDF.
>>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. Be Safe and Happy. Thanks.

Good Luck

Respectfully

John

PS: I am Allowed to Answer 5 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. Comments and Ratings are Greatly Appreciated. Thanks.

Respectfully

John