Fuel shutoff Solenoid problem

B

Bewildered

New member
Hello, got a Hitachi trackhoe that had a bad shut off, got a replacement from Amazon which was the exact type as the old one but it would not click on when put in the engine using the same wiring harness. Mechanic thought we had weak power coming from the ignition switch so he ran a wire direct from the battery through a toggle switch to test it and then it worked..

The problem is that it gets real hot after a short time running so got some advice that there is some bad wiring and since there was 3 wires to the solenoid, the idea is strong current needed to activate and then it should go to a weaker field which just holds in in place with less amps but it is running at full amps which causes it to overheat.

Anyone here have a solenoid that runs hot? There is a red, white and black wire but the wiring in the engine has power being white, ground black and nothing happens when hooking to the red wire. Any idea what the red wire is for? Thanks
 
'Gets real hot" using what? The machine's wiring or the battery jumper wire? If it has three wires (one being ground) then which of the other two pulls it in and which one holds it in? Only the hold circuit should be powered with key switch on. The other is more momentary, like when starter is engaged.
 
When using the plug in from the engines wiring which comes from the ignition switch, It would not"click" so we just tested the solenoid without it being plugged in using the machines battery and then it would click so mechanic thought there must be a power leakage using the ignition circuit. Wire.. just wanted to make sure the new unit was working like it should.

When we plugged it back into the engine wiring and used the key to start, it would not click but if we pushed the rod in it would stay in and when key turned off it would pop out like it should.

So we installed it with the rod pushed in so it would start but after about 5 minutes of running, we felt the solenoid and it was hot and not from the engine block heat so another opinion from another forum thought both hot wires must be staying on which is causing the heat.

The previous owner had done a real frankenstein of a job fixing wiring, piggybacking on other circuits, melted the fuse box so we are trying to fix all the mistakes.

Today I checked one of the wires going back into the flex conduit found they changed the color from red to white so those wires are plugged in backwards
 
No wonder you have problems. The wiring situation could well be the reason the original solenoid went bad in the first place. Hitachi is a name brand machine, so can you find a proper wiring diagram to match the unit? Or have you already tried that route and come up empty? I've seen other machines both Korean and Japanese that use a three wire fuel stop solenoid, yet only power and ground wires connected. They seem to work well enough. I guess it depends on the solenoid itself.
 
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