Key switch magnum engine

[Goldnboy 927]

I acquired thus switch from I save tractors and wanted to make sure that the G terminal can be hooked to the rectifier? 

L = accessory

M= magneto

S= start

G=?

B=battery

[953 nut 55,393]

What is the number of that switch?  "G" is GROUND in most cases.

 

[Handy Don 12,281]

 

It’s possible G is for generator, but unlikely IMHO.

A magneto engine needs ground to turn it off (typically in OFF position, M+G+A are connected -- you can test with a VOM).

[gwest_ca-(File Mod) 11,070]

What is the model number of the tractor? and what year?

With that we can determine the correct switch.

[Goldnboy 927]

The model number of the tractor is a C120 however I removed a magnum 12 from a 312-8 and do not have the old key switch 

 

There are two wires from the engine purple (magneto) and white from the rectifier. 

 

I was using the diagram for a magneto engine but my terminals are marked differently. 

Here is the details on the switch from I-save tractors:

 

This is a 5 Terminal, 3 Position Ignition Switch. Works for all Vintage Garden Tractors and Kohler K Series and Magnum Engines that use a Magneto Ignition System

The terminals are for Battery, Ground, Lights, Starter, Magneto

Fits all Magneto Ignition Kohler K Series and Magnum Engines! For all models of tractors. 

• The terminals are for Battery, Ground, Lights, Starter, Magneto
• 5/8" Mounting Hole
• Circuit Design: Off: Magneto + Ground Run: Battery + Lights Start: Battery + Start + Lights

Edited June 30 by Goldnboy

[gwest_ca-(File Mod) 11,070]

You need to remove the terminals from their plastic holder and insert them to match your switch. What you have is not 103991.

The rectifier output can go to the L terminal.

Here are the terminals used. Click on the picture and read instructions.

 

[953 nut 55,393]

If you have not cut or otherwise modified any of the wiring on the C-120 there is an easy way to solve the problem. Start with the 103-990 which was correct for the C-120 and add a kill relay as shown in the attached thread. This must be done to avoid having to rewire all of the other components and safety switches.

 

 

[Goldnboy 927]

1 hour ago, 953 nut said:

If you have not cut or otherwise modified any of the wiring on the C-120 there is an easy way to solve the problem. Start with the 103-990 which was correct for the C-120 and add a kill relay as shown in the attached thread. This must be done to avoid having to rewire all of the other components and safety switches.

 

 

I thought about that but...I had a wire setup for the Tecumseh HH12 so and it had many splices already so i when all new wires...

[Goldnboy 927]

Thanks for confirming I realize I have the wrong key switch...didn't think the older Magento engines switch were different...

 

I guess question on wiring the 103-991 which I can get Monday does it matter where the ground hooks to that will run to key switch?

[gwest_ca-(File Mod) 11,070]

The metal body of the switch is grounded as you will see that G terminal is tied to the body of the switch. The G terminal just requires a good battery ground. The reason for such a design is the switch is often mounted in a plastic or fiberglass panel witch does not supply a ground.

 

Adding a relay to your present wiring to control the ignition is a simpler way to do it. The relay is available in Canada with a plug in socket which is a sound modification. Most of the last tractors use a battery ignition switch to control their magneto ignitions. Often labeled as a kill relay.

https://www.princessauto.com/en/30a-12v-dc-change-over-relay-with-socket/product/PA0008402034

Similar to Northern Tool.

[kpinnc 12,174]

The tab on the side that connects to the outer case is a dead giveaway: That is the ground. 

 

When in doubt, break out your multimeter. If the key is in the "off" position, you should see a solid short between the "M" and the "G" terminals, as this grounds the magneto and interrupts the spark. 

 

 

Edited July 1 by kpinnc

[Goldnboy 927]

I finished putting in the  103-991 and added the sixth wire ground to the G terminal. 

 

Now that I hooked up the battery I turned the key and nothing happened.

 

I double checked the connectors were on the new key correct  and grounds are good..

 

So where can I start? Since the starter didn't crank?

 

[gwest_ca-(File Mod) 11,070]

When you turn the switch to start the S terminal should send power to the small terminal on the solenoid. The solenoid should thump and send battery power to the starter.

[Goldnboy 927]

D

2 hours ago, gwest_ca said:

When you turn the switch to start the S terminal should send power to the small terminal on the solenoid. The solenoid should thump and send battery power to the starter.

Now that i realize this is start circuit  does the solenoid  "I" terminal need to be grounded? Normally I hook nothing to it...

 

[953 nut 55,393]

12 hours ago, Goldnboy said:

D

Now that i realize this is start circuit  does the solenoid  "I" terminal need to be grounded? Normally I hook nothing to it...

 

Is this a FORD solenoid?          If it is then nothing goes to the "I" terminal of the solenoid.    If it is a regular garden tractor solenoid then one of the small terminals will need to be grounded, either one is fine.

[Goldnboy 927]

I now have the starter cranking...bad new out of box solenoid from Amazon...picked up new one from O'Reilly.