Goldnboy 927 #1 Posted June 29 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 Share this post Link to post Share on other sites
953 nut 55,394 #2 Posted June 29 What is the number of that switch? "G" is GROUND in most cases. 1 1 Share this post Link to post Share on other sites
Handy Don 12,282 #3 Posted June 30 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). 2 Share this post Link to post Share on other sites
gwest_ca-(File Mod) 11,072 #4 Posted June 30 What is the model number of the tractor? and what year? With that we can determine the correct switch. Share this post Link to post Share on other sites
Goldnboy 927 #5 Posted June 30 (edited) 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 Share this post Link to post Share on other sites
gwest_ca-(File Mod) 11,072 #6 Posted June 30 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. Share this post Link to post Share on other sites
953 nut 55,394 #7 Posted June 30 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. 2 Share this post Link to post Share on other sites
Goldnboy 927 #8 Posted June 30 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... Share this post Link to post Share on other sites
Goldnboy 927 #9 Posted June 30 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? Share this post Link to post Share on other sites
gwest_ca-(File Mod) 11,072 #10 Posted July 1 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. 1 Share this post Link to post Share on other sites
kpinnc 12,175 #11 Posted July 1 (edited) 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 1 1 Share this post Link to post Share on other sites
Goldnboy 927 #12 Posted July 4 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? Share this post Link to post Share on other sites
gwest_ca-(File Mod) 11,072 #13 Posted July 4 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. 1 Share this post Link to post Share on other sites
Goldnboy 927 #14 Posted July 4 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... Share this post Link to post Share on other sites
953 nut 55,394 #15 Posted July 5 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. Share this post Link to post Share on other sites
Goldnboy 927 #16 Posted July 5 I now have the starter cranking...bad new out of box solenoid from Amazon...picked up new one from O'Reilly. 1 Share this post Link to post Share on other sites