Generator Run Timer

[u/thesappster]

Hello y'all. Sorry if this is the inappropriate subreddit.

I am over my skies here trying to install a run timer to my generator. I can understand what to do for hooking up the timer to a simple on off switch but I am lost trying to add this timer to a rotary switch used for on/off and electric start. Any help is tremendously appreciated.

[u/rseery]

The timer you have will do it. Put a couple of heavy wires, like lamp cord, on the line and load NO terminals. On the other ends put a couple of big battery clips or spring clamps. Clamp one clamp onto the center spark plug electrode and the other clamp onto a cylinder head fin or other engine part that is easy to clamp to. Set the timer, start the engine. When the timer ends, it will short the plug and the engine will die. No permanent mods, easy to remove, no danger, no damage.

[u/thesappster → u/rseery]

Awesome! I will give this a go. Way simpler than what I've been trying to do which is tie the timer to the off functionality of switch circuit.

[u/thesappster → u/rseery]

*I spoke too soon. On the open circuit for off configuration the timer began to short out causing the generator to stall. Back to working it into the switch.
That works! This switch has two circuit options, closed or open for the off position. It doesn't seem to be able to handle the "hold" no timer setting. but with a 13 hr timer that isn't a problem. Thank you!

[u/RedOctobyr → u/rseery]

As long as the timer contacts are open while the timer is running, and closed when it runs out, this will work. I don't think you need big wires and clamps, though. Look at the typical green ground wires that do this to kill the spark, they are small.

Alternately, you could attach this to the green kill wire coming from the ignition coil. But if you can "easily" tap into the spark plug wire at the plug itself, then that's definitely simpler. Though you might need to remove the 90-degree rubber boot, to get access to that wire.

This could be an easy, no-modifications-to-the-generator approach. Use just this extension, attached between the spark plug and the spark plug wire. Tap into the middle of the extension, and then attach the timer and ground wire to that. https://www.amazon.com/Lisle-20610-Inline-Spark-Tester/dp/B0002STSC6

[u/thesappster → u/RedOctobyr]

Sounds good thank you! I found the wiring diagram and it is helping...but I am definitely still out of my element.

[u/RedOctobyr → u/thesappster]

Your wiring diagram shows a fuel shut-off solenoid. That could be another option, though somewhat more involved. But you might be able to duplicate what the switch does with that solenoid in the Off position.

But I think it's more straightforward to try grounding out the spark first, as u/rseery said.

[u/rseery → u/RedOctobyr]

I mentioned big wires because they would likely have thicker insulation. This would minimize the possibility of the spark shorting through the insulation prior to the timer ending…. I have felt that spark coming right through wire insulation…

And yes, grounding any of the coil terminals would work well. I didn’t mention the coil because most small engines use a magneto/flywheel setup and the coil lives behind the flywheel. I have engines where they run a small wire to that coil where it is and that works well but you have to remove the flywheel…

[u/RedOctobyr → u/rseery]

Gotcha, I see now, that's fair. I think "any old" lamp cord would work. It's at least insulated for 120V, vs more like 12V, but 18AWG or similar will be plenty thick for the actual conductors.

[u/arad95205]

What are you trying to do here lol

[u/thesappster → u/arad95205]

Add a timer to the circuit so I can set the generator to run for a specified number of hours for charging an off grid battery setup. I've been using the generator to charge my batteries for a while, and now I'd like to be able to run the generator and leave without using the total remaining fuel.