Magneto Kill Switch Wire Shorted to Ground

[Grousemansav]

Ok so my Craftsman lawn mower was working fine until this morning. It is a 2002 mower with a 6 ½ HP Briggs & Stratton Model123K02-02260E1 engine. I used my spark tester hooked up to the spark plug and there was no spark. So then I hooked the tester directly to the block and there was spark. I changed plugs but still the same results. So I’m thinking it must be a really weak spark. I cleaned the magneto and reset the flywheel gap to one business card thick. Still the same results.

Then I looked at the kill switch and everything looked OK. I unhooked the kill switch wire and put my VOM between the wire and the block and there was 0 ohms resistance which says to me that the kill switch wire is shorted to ground. I checked the condition of the wire back to the magneto and it is good.

As far as I can figure, that wire from the magneto should not be shorted to ground until the kill switch closes for safety. That being the case I figure it must be internally shorted in the magneto and I need to replace the magneto.

I am relatively new to this so would really appreciate any input from experienced repairman.

Stay safe, Grouseman

 

[Rivets]

If you believe everything you see on the internet then you can follow that guy’s procedure and replace the coil. I don’t believe half of what I see, but I have been wrong before. I have not found a reliable way to test today’s coils which contain a Hall effect module in them. I suspect you have a short in the wire between the coil and the kill switch which is located by the flywheel brake. Before I would spend money on a new coil I would triple check this kill wire. Just my opinion, as you can see by my signature isn’t worth much.

 

[Grousemansav]

If you believe everything you see on the internet then you can follow that guy’s procedure and replace the coil. I don’t believe half of what I see, but I have been wrong before. I have not found a reliable way to test today’s coils which contain a Hall effect module in them. I suspect you have a short in the wire between the coil and the kill switch which is located by the flywheel brake. Before I would spend money on a new coil I would triple check this kill wire. Just my opinion, as you can see by my signature isn’t worth much.

I checked the kill switch itself thoroughly and it is functioning properly. The insulating sandwich where the wire attaches is working fine.

Grouseman

 

[StarTech]

To determine if it is coil or the kill circuit disconnect the kill circuit at the coil's kill terminal and test.

 

[bertsmobile1]

remove the kill wire at the magneto
Put your spark tester on the plug and lay the plug on the block
Spin the flywheel and see if you have a spark

 

[Grousemansav]

OK so now the plot thickens and I am totally confused. Yesterday I disconnected the kill switch wire and put everything back together. Low and behold it started right up. I had to pull the plug wire to stop it. This is really baffling!! Now I'm thinking it's got to be the kill switch but why is the kill switch wire shorted to ground at the magneto? Help!!!

Grouseman

 

[Rivets]

The kill switch wire on the coil (the one you removed) goes from the coil to the kill switch which is located by the flywheel brake assembly and shorts to ground when you release the bail handle . By removing the wire you disabled the kill switch. If the wire is bad or shorted to ground, it will acted like a kill switch and the engine will not run.