need wiring diagram for Murray # 42508x92 Riding Mower?

Bought this unit last year, w/o the deck, for the engine. Drove fine. Now ... no fire! Tried manually depressing the safety switches and still no fire. Could also use a test sequence with voltage specs and resistance, if available. No show at Murray or Tecumseh. The engine is a Tecumseh 17.5 Enduro XL/C, model: OHV175 ..... 204803 (H). I have automotive mechanical background but, rather lost at this point. Any help greatly appreciated .... grass growing rapidly!

Jim Kimbrough
April 2008