aloha
Silver Member
- Joined
- Dec 3, 2003
- Messages
- 213
- Location
- Hawaii - Big Island
- Tractor
- Kubota B7800 / Kubota RTV X900 / Scag Turf Tiger
I am troubleshooting problems with my Scag powered by a Kohler 27 hp CH740 engine. The general thread for my struggles is at http://www.tractorbynet.com/forums/general-lawn-garden/218393-scag-kohler-engine-has-me.html, but there is a specific issue I have run into involving the engine's kill circuit.
If I understand the service manual for the engine, the kill circuit works by grounding the ignition modules to prevent the spark plugs from being energized. And, if I understand the service manual correctly, if the kill circuit is disabled the engine, once started, will continue to run until stopped by some other method such as shutting of the fuel. If I have misunderstood the manual, please correct me.
My problem has been that the spark is being killed with the ignition switch in the run position as well as off position. I do have spark when the ignition switch is in the start position.
When I disconnect the wires identified in the wiring diagram as "kill" from the ignition modules I get no spark even when the ignition switch is in the start position. There is another wire to the ignition modules identified as "trigger" so I tried disconnecting those to see if the diagram had wire labels reversed, but got the same result--no spark at all. I have also tried disconnecting the white wire emerging from the spark advance module which the diagram labels as "kill" and get the same result--no spark, even in the start position.
If someone can correct my understanding of the kill circuit, or how to disable it, or make any sense of this, I will be most grateful. Thanks.
If I understand the service manual for the engine, the kill circuit works by grounding the ignition modules to prevent the spark plugs from being energized. And, if I understand the service manual correctly, if the kill circuit is disabled the engine, once started, will continue to run until stopped by some other method such as shutting of the fuel. If I have misunderstood the manual, please correct me.
My problem has been that the spark is being killed with the ignition switch in the run position as well as off position. I do have spark when the ignition switch is in the start position.
When I disconnect the wires identified in the wiring diagram as "kill" from the ignition modules I get no spark even when the ignition switch is in the start position. There is another wire to the ignition modules identified as "trigger" so I tried disconnecting those to see if the diagram had wire labels reversed, but got the same result--no spark at all. I have also tried disconnecting the white wire emerging from the spark advance module which the diagram labels as "kill" and get the same result--no spark, even in the start position.
If someone can correct my understanding of the kill circuit, or how to disable it, or make any sense of this, I will be most grateful. Thanks.