1986 Techumseh OH 160 Wiring Question

[Dworth]

Hello all

My first post is a question. Go figure eh?

I have an Argo 6x6; I believe 1986. The old owner installed an electric fuel pump controlled by a switch. I wouldn't say I like it... I want to figure out where the fuel pump will only turn on when the engine is running.

So far, I figure connecting a relay where the charging coil goes to the battery's positive pole. I thought the amperage made by the charging coil would trigger the relay.

I feel slightly lost, but I know there is some way.

[Laird]

You could wire it into the ignition so when the key is in the run position the pump works. Eliminates the pump switch.

[Dworth]

Only issue I've ran into with that is the key in the off positions makes a connection in order to kill the engine, instead of breaking a connection.

[Dworth]

You could wire it into the ignition so when the key is in the run position the pump works. Eliminates the pump switch.

Wiring.jpg

So far the issue I have is that the positive line going from the charging coil to the battery constantly has 12v but no amps, when running the charging coil creates a roughly reliable 6 amp charge on the battery. I was hoping a normal relay would work because of the minimum amperage needed to activate. But since there is no ground it doesn't trigger and I know grounding the coil will damage it.

So my thought is so figure out maybe an amperage-activated relay.