Wiring a Vanguard 303777-111-A1

Hello all,
I have an older JD LA-110 that I am Frankenstein-ing a Vanguard twin into. (This is actually the second engine swap from the original as first I put in an old Kawasaki FB460)

I've got it physically installed, worked in a separate choke cable, and am now looking to get it wired up but can't seem to find much in the way of wiring diagrams. Ideally I'd like to find the wiring layout of a tractor it came in but buying it second (or third) hand I don't even know what tractors this was available in.

Any thoughts or directions would be very appreciated... this is my little plow tractor and like it or not, winter is coming!

Doug

FWI forget about which tractor it came from and look at the engine , most engine manuals are generic and cover a variety of engines. The attached may be of some help , take a look at SEC 2 , covers the electrical systems. No guarantee it's exactly what your are looking for .. copy and paste it in to your search ..

https://www.casecoltingersoll.com/d3/manuals/ServiceManuals/Briggs%20and%20Stratton%20Vanguard%20Engine%20Manual%20%20272144_watermarked.pdf

Do you have an volt-ohm meter?

There are only 3 circuits on the engine itself. (Unless it has the dual circuit stator and that has a small 2 wire plug with a red and
white wire.)

1. Alternator/charging. If you remove the flywheel cover, you can see it coming from the voltage regulator. I am thinking Briggs always
uses a red wire for this. You may see it jumped to more than one pin if the Vanguard engine has a 6 pin plug. On the mower harness,
sometimes this wire is hot (12v) all the time, sometimes it switches off with the ignition switch. I don't know which way Deere chose to
do it.

2. Fuel solenoid. The little coil under the carburetor. I am thinking this would be a grey wire. This wire is always hot (12v) with the
ignition switch turned 'on' or in 'start' position and off (0 volts) with the ignition switch off.

3. stop wire or 'kill' wire from the coils. This wire is black on most other Briggs engines, but I am unsure on Vanguard engines. this
wire will never have 12v. on it, but it will be grounded through the ignition switch when the key is 'off'.
Some important things to note: A. the kill wire between the coils has diodes in it so they don't damage each other. Because of this it
cannot be replaced by just a piece of wire. B. NEVER NEVER EVER PUT 12V. ON THIS KILL WIRE UNLESS YOU WANT TO REPLACE THE IGNITION COILS!.
That is why I asked if you had an volt-ohm meter.

This is why you need an ohm meter. So you can determine which wire does what on the plug/wires/whichever it is mower chassis.

Thank you both!

I ran through and did a continuity test on the key switch, of which the diagram is below.

Any thoughts on connection of the power line from the voltage regulator?
1) Connect into the wiring from the key switch?
2) Run directly to the battery?
3) Run to the battery post on the starter solenoid?

Otherwise, I think this works. Thoughts?

Regards,
Doug

Ideas 2 or 3 will work and would be simpler than #1. #3 going to the solenoid would be the neatest installation.

For idea #1, there is probably some way to do it-maybe connect the regulator wire to L or A2 if either is 'on' (12v positive) with the key
in run and 'off' with the key off.

Just one thing to be aware of when using idea #2 or #3: If your battery starts going dead while the unit is stored, its probably the voltage
regulatior that is using the current. About all voltage regulators use some current in their circuitry when the engine is not running.
Sometimes this is no problem, but with some voltage regulators it will kill the battery in two weeks or less.