B&S Wiring Diagram

[kpike52]

The B&S 18hp motor is finally back. But all of the wiring is gone. Does anyone have info on a wiring diagram? I can see a 2 prong plug which is likely the 12v out?

[jpswift1]

It's pretty simple, but I'm not good with wiring or explaining it. 6X6World member Racerone3 would be able to point you in the right direction. He knows these engines inside and out. Is this the flat twin Briggs I/C or the V twin Briggs Vanguard?

[hydromike]

The opposed Briggs engines only have a 12V out from the voltage regulator (on the top-rear of the engine) and a kill wire hooked up to the magneto, which plugs into a receptical on the upper-front of the engine. Outside of a starter wire, that's it.... I've never looked at the wiring on a Vanguard, so you'll need someone S-M-R-T'er than I for that one.....

::EDIT:: Wait, is it THIS engine, from almost a year ago?

As part of my Hustler rebuild I am letting the high school small engine shop class check out my 16hp B&S.

[kpike52]

Yes, this is the engine from a year ago. It took 3 semesters to complete. (don't ask). It is an IC. There is a 3/16" spade terminal on top too. It looks like a frame ground.

[hydromike]

There is a 3/16" spade terminal on top too. It looks like a frame ground.

It does look like a frame ground, but this is the kill switch wire for the magneto. It connects to the "Mag" or "M" labeled terminal on your ignition switch. Look at it closely, and you'll see it's actually insulated from ground. A ground wire from the engine to the frame should be a beefy wire, about the same gauge as a battery cable.

[kpike52]

Ok that makes sense except I do not have a wiring harness anymore with the ignition switch. All the wiring went out with the motor but did not come back.
The mag has a spade on the top side opposite from the spark cables. This motor has points and a wire is connected from the mag spade to the points. (Side question - How do the points and mag working together to create the ignition spark duration?) Is this the wire that also connects to a kill switch circuit that shunts the mag to ground?

[racerone3]

You probably have the briggs "magnetron" ignition and not points. Go grab a lawn tractor 5 pole switch from lowes and some wire.
Here is how to wire it up-
12 gage wire from battery + to the "B" pole on the ignition switch. Use red wire to denote positive.
14-16 gage blue wire from "S" pole on switch to the small pole on the solenoid [called the "exciter wire] (use a solenoid for an 80-s ford truck).
Black 12 to 14 gage wire from chassis ground to the "G" pole on the switch... also include a second wire off the switch for a headlight ground
Green 14 gage wire from the "M" (magneto) terminal on the switch to the small spade you found on top of your engine.
From the single red wire on the voltage regulator, you can run directly to battery +, but i prefer to run a wire up to the "L" (lights) terminal on the switch and include another wire from L to your headlight switch. This keeps power from backfeeding through the regulator when power is off. Also run a good ground from battery- to the frame and engine block. Red Battery cable from battery positive to one large pole on the solenoid and another from the other large pole to the starter.
Hope this sets you off in the right direction. If you need any other help let me know

[kpike52]

Thank. Excellent.