Small Engines (Lawn Mowers, etc.): 18hp twin B&S Coil, two inlets, lawnmower engine

Question
I am in the process of replacing a lawnmower engine, with a 18 hp B&S 422707 L head twin opposed engine. Everything seems to fit perfectly, but I'm touch confused about the coil. It has the two plugs wires coming out, and a small black wire. I have no idea were that small wire goes or it's purpose. I also am a little confused with the fuel lines, it has the fuel pump with two inlets. Does one connect to the crankcase to power the diaphram? If so, is it the inlet on the bottom or on the side? Thanks so much for your time, and any knowledge you could provide.

Answer
The black wire is for the engine shut-off switch, which connects to ground when you turn the key off to shut off the engine.

One end of the fuel pump connects to the crankcase for vacuum..the other is for fuel...can't remember which is which but I will check.

Eric