Having trouble with my tractor not shutting down when I turn the key off. some times it will run a few second then die and other times it takes a couple of min. is the switch bad? what do I need to check? tractor has a 4:239
On your injection pump there are two terminals(studs) that lead to the Fuel hut-Off Solenoid(9).
A (Hot) wire from the ignition switch feed voltage to one terminal.
The other terminal is connected to Ground, via a short length of wire(3) or a flat metal strap(Ground).
When the ignition switch is turned to the ON position, voltage is sent to the (Hot) terminal to Excite the Solenoid(9), which pulls the Arm(13) toward the Solenoid. This allows fuel to be supplied within the pump.
When the ignition switch is turned to the OFF position, the voltage is stopped to the Solenoid(9). The Arm(13) moves away from the Solenoid(9) and shut off the fuel supply within the pump.
Using Voltmeter, to check if voltage is present the Hot terminal, with ignition switch ON and that the voltage drops when the ignition switch is OFF.
If voltage is present at the Hot terminal, when the ignition switch is in the OFF position, there is a problem with the ignition switch.
If voltage is dropped when the ignition switch is in the OFF position, there is a problem with the solenoid, or the metering valve(14 in diagram below) within the pump.
The Cover(7 in diagram above) can be removed to verify the movement of Arm(13).
Your pump apparently utilizes a Metal Strap for Grounding purposes.
The image below is for reference ONLY.
The Metal Strap connects the NEGATIVE Terminal of the Shut-Off Solenoid to one of the Pump Cover retaining screws.
When the Ignition(key switch) is in the ON position, there should be voltage(12 volts) to the Voltage Supply Terminal. This will activate the Solenoid and allow the Metering Valve(within the pump) to supply fuel to the delivery head of the pump.
When the Ignition(key switch) is in the OFF position, there should be NO voltage to the Voltage Supply Terminal. This will allow the Solenoid to move to the Shut-Off position, terminating the fuel supply to the delivery head of the pump.
If the Ignition(key switch) is in the OFF position and Voltage is present at the Voltage Supply Terminal, there is an electrical problem somewhere in the wiring harness.
With the Ignition(key switch) in the OFF position and there is NO voltage present at the Voltage Supply Terminal, the problem is most likely with the Fuel Shut-Off Solenoid.