Engine shutdown

[chriswheeler]

My YM 3000 and JD 950 O&M manuals says the same thing. We had a mid size Cat V12 generator that had compression release valves on both banks of the engine. 50's vintage, about 900 hp. Instruction manual stated that this was to be used in case of emergancy shut down and not under normal conditions. Normal shutdown was the same as most, by closeing the rack to the fuel pump. I suspect that most are the same, shutting off the the fuel rack. Decompression works well for starting these small engines on a cold morning, building up oil pressure first before starting. Would never use to shut down unless it ran away and their was no other way to shut it down.
Chris

 

[svcguy]

We are actually talking about two different systems, key vs pump. When a diesel is shut down, you simply cut off the fuel supply or the air supply. Either one will kill the engine. On most tractors, especially older units, this is done with the throttle lever. You run the throttle down to idle, then past that point with the throttle lever, which cuts the fuel delivery at the fuel injection pump and that stops the engine. This type of tractor is the type where it is recommended not to turn your ignition off until after the engine stops (ignition switch is for the charging system). Other tractors use a 12 volt actuator or solenoid to cut air off at the intake manifold. This is the type that when you turn the key on, it opens the air intake and with the key off, it shuts the engine down by shutting off the air supply. Both work well, but the first type is where you don't want to turn the key off until the engine has stopped.

 

[xlr82v2]

Which tractors choke off the intake to kill the engine? I've never seen one like this...

All the tractors and any other diesels that had key operated kill systems had a solenoid on the injector pump that electromechanically moved the rack to cutoff instead of doing it manually via a knob and cable or with the throttle.

 

[svcguy]

An example of a solenoid air shut down is used by Iseki. The TU series use the 'choke' type shutdown. You are absolutely correct though, many use the same system on a pump, either air or fuel.

 

[choffman41]

Remember the old GMC 71 series diesels, regular shutdown was by shutting off fuel, but there was also an air block for emergency shutdown for runaways.