Small Engines (Lawn Mowers, etc.): B&S 18 hp model #422437, safety switches, hp model

Question
I was given this rider and told that it does run.
However I have no key and would like very much to make sure that it runs before I spend money on it.
The question is where can I find a wiring diagram on the net or what wires do I need to make hot to get it to run? I've got it to turn over but there is no fire. I have not disconnected anything or any of the safety switches either. I am hoping to find out how to by-pass all that temporarily. I know cars but not small engines. Thanks in advance

Answer
Somewhere on the engine block there will be a black wire spade terminal connector.  Dis-connecting this wire will isolate the coil and you should have spark.  You can also remove the top sheet metal on the engine and dis-connect the wire from the coil.  This is the primary coil grounding wire.  When you turn the key off,  or get off the seat with the blades engaged, the coil is grounded which prevents spark.  

Does this make sense?
Eric