Ask the Mechanic

Kill the Engine

(Steve Thompson)

READER: I have a Kubota BX2350 that won't die with the key switch. Most of my life, I have had a more difficult time getting a diesel engine to start than getting it to die. But, this little tractor is different -- it won't die when I turn off the key. My other Kubota tractors that I have owned could be killed with a pull knob, if needed, but this tractor doesn't have a kill knob. I called my neighbor who tinkers with tractors the first time it would not die, and he told me to take off the rubber air intake hose coming from the air cleaner to the air intake on the engine and cover the air intake on the engine with a flat piece of wood. It worked, but now I would like to know if there's a better way to kill it until I can get it fixed?

STEVE: Yes sir, there is a better way to kill it. The electric kill solenoid on this tractor is different. It is activated through a relay when the key is turned off to kill the engine. The solenoid is not a continuous-duty type, so it can't stay energized for very long, or it will burn out. So, soon after the key is turned off, the relay energizes and activates the solenoid, killing the tractor. After it is on for this short time and kills the engine, a timer turns off the relay, and the kill solenoid returns to the run position, ready to start.

You have a problem somewhere in that kill circuit, but in the meantime, I have good news. You can manually kill the engine by raising the hood and looking straight down under the air cleaner. There you will see a screw on top of the injector pump that is painted red. Reach down and pull the screw back toward the rear of the tractor, and the tractor will die. That is your emergency kill for this tractor.


-- Write Steve Thompson at Ask The Mechanic, 2204 Lakeshore Dr., Suite 415, Birmingham, AL 35209, or email, and be sure to include your phone number.


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