unverisal M12

[santana30RI]

Good after noon. I have a unversal m12 it starts up but rev high 3400+ and when try to kill the motor it wil lnot stop i have to pull the fuel supply what could it be?

[KBuckley]

We need more info. What is the history of the engine, is this problem new, is the engine/boat new to you? Do you mean you need to pull the fuel shutoff knob (normal) or you need to pull off a fuel line?

[santana30RI]

Motor is new to me. i start the motor and right off the back it rev to max the throtel does nothing and to kill the motor off i have to pull the fuel line it self off

[rugosa]

Originally Posted by santana30RI

Motor is new to me. i start the motor and right off the back it rev to max the throtel does nothing and to kiss the motor off i have to pull the fuel line it self off

First check if throttle cable is connected at control and engine.

[jkrause]

Not wanting to state the obvious, but the M12 is a diesel engine. You don't turn it off by turning the key (or pulling out the fuel line). There should be a throttle cutoff handle near the controls (T shaped handle). Pull out the handle to kill the engine- then turn off the key.

[JimsCAL]

Originally Posted by jkrause

Not wanting to state the obvious, but the M12 is a diesel engine. You don't turn it off by turning the key (or pulling out the fuel line). There should be a decompression handle near the controls (T shaped handle). Pull out the handle to kill the engine- then turn off the key.

Just to clarify, diesels are stopped by cutting off the fuel. Some have a handle, some you pull the throttle back past idle, and some have a solenoid valve in the fuel line that is shut when you turn the key to off. It is not good practice to stop a diesel with the decompression control.

[jkrause]

DOH! - That's right- On my Catalina 27 (with a Universal M18) you pull the throttle cutoff (T-shaped) handle. Look for that or a kill button, usually located near the ignition. Then turn off the key. (Earlier post re-edited - Thanks JimsCAL for pointing out this glaring error).

[santana30RI]

the motor is on a stand not in the boat
the stop lever will not kill the motor
the throttle is in idel spot and moving it does nothing
i stop the motor by pulling the fuel line off the motor

[chucklesR]

If the throttle isn't doing anything then that is your first clue.

Fix the throttle. It's stuck wide open - check down stream of it - fuel rack, injector etc.