I have owned a troy built riding mower for about 5 years now with a 17 1/2 hp motor. The motor blowed and a friend gave me a 12 hp to replace it with. I have everything replaced but need a wiring diagram or instructions to get it fixed. It/s beyond me. I have tried.

Hi,
Could you provide the mowers model number (under the seat) and the engine model number (black and silver tag riveted to th blower housing) so that we can know what you are working with. A few variations are possible.
Peace,
Clarke