Engine doesn't fire when starter engaged

Nosoup4u · Sep 17, 2008

I"ve been fixing up a 454 IH utility. I installed a new wiring harness, and when I try to start it it will not fire until I let off the key switch. I confirmed this by pulling one plug wire and attaching it to a plug. I never get a spark, until I stop cranking it. I would bet this is something very simple, but then I"m pretty simple too.

Bigdog · Sep 17, 2008

Sounds like the ignition line is connected to the wrong terminal on the switch. Re-check your connections.

Nosoup4u · Sep 17, 2008

Entirely possible. I had the switch out, but even after cleaning it was hard to read the little marks on the back.

rustyfarmall · Sep 17, 2008

I'm thinking that there should be a connection that supplies a full 12 volts to the ignition when the switch is in the "start" position, and then after the engine starts, and the switch is returned to the "run" position, only 6 volts is supplied to the ignition. You are either missing one of those connections, or the switch has gone bad.

steveormary · Sep 17, 2008

When the starter is engaged it lowers the voltage to the coil and you get no spark. When you let up on the starter the engine is still turning over and you get full voltage to the coil,hence a good spark at the plugs.

I have had several tractors like that. Mostly Farmalls.

steveormary

Dellbertt · Sep 17, 2008

If that is the case how would you know when to let off the starter. Usually you let off the starter when it fires.

dwag · Sep 17, 2008

The "R" terminal on starter solenoid supplies full voltage to + terminal on coil during cranking. As suggested earlier, you have a wiring problem. You may have to run/make a wire from "R" terminal to coil if one not included in harness. "R" terminal is one of the two small posts on solenoid, the other one being marked "S" .

47M · Sep 17, 2008

I had the exact same problem on my old Harley Sportster a year ago. When I'd push the start button, it would crank and crank and crank but wouldn"t start until I let go of the starter button.

My problem turned out to be corrosion inside the plastic sheath of one of the battery cables. Of course, I didn't find the problem until after I bought a new battery and started to replace it. The bad cable was apparently passing enough current to turn the engine over, but dropping enough voltage to not fire the plugs.

(Something else to check in case you find your wiring is correct.)

Mitch

steveormary · Sep 17, 2008

Dellbertt;

I read it on YT. I engage the starter for only a few seconds and if the engine dont start I let off the starter switch and try again.

steveormary

Engine doesn't fire when starter engaged

Nosoup4u

Member

Bigdog

Well-known Member

Nosoup4u

Member

rustyfarmall

Well-known Member

steveormary

Well-known Member

Dellbertt

Member

dwag

Member

47M

Member

steveormary

Well-known Member

Similar threads