3 pronged ignition switch fails to ground magneto

[Tchmbrs1]

This is my first dive in repairing a small engine riding mower.

I have a Snapper rear engine cruiser series 15 with a 12HP briggs and stratton L head engine.

So far I have the engine starting, and and the kill switch circuit going through the seat and neutral switch is working. But when I turn the key to off the engine does not cut off. I tried finding out how the ignition switch grounds the magneto lead, but I can't find any useful information after doing some searching. I believe the M terminal should short to ground through the body of the switch, but continuity tests don't confirm this.

Do I have a faulty ignition switch? Or am I missing something on how this switch grounds out?

 

[dougand3]

Need the Snapper model #. And Briggs # would help - eg: 28A707-12344-E1

 

[Tchmbrs1]

Snapper Model 301215BE
Briggs amd Stratton Model 283707 0136-01

 

[dougand3]

Wiring diagram...
https://www.partstree.com/models/30...ing-schematic-for-9-10-12-and-16hp-briggs-21/

 

[Tchmbrs1]

Wiring diagram...
https://www.partstree.com/models/30...ing-schematic-for-9-10-12-and-16hp-briggs-21/

Right, so that is the same diagram I have been working off of.

But how does the M terminal of the ignition switch connect to ground? Just one magneto wire going from the engine to switch doesn't make a complete circuit unless the switch is suppose to ground through the body of the switch.

Thank you so much for your time and input!

 

[bertsmobile1]

The key switch will have a ground wire on it and the switch connects the G & M wires together in the off position.

 

[dougand3]

If you have only 3 terminals...is it Battery - Starter - Magneto? If so, the switch body must ground thru the metal dash mount. Try this - Get multimeter in ohm setting - one lead on M, other lead grounded, switch in OFF position. Should show resistance or just use continuity setting.
Re-read 1st post - you did this and no continuity. Sounds like a bad switch.
Most switches now are 5 terminal - esp at Oreilly, AZ, etc. You could use one and add a G wire, forget L & A. Or buy a 3 terminal online.
Have you pulled blower housing and looked at coil and followed kill wire? Then, you can test coil. It's running and won't stop with key...then ground the coil kill terminal and should stop.