Timing Tractor Injection Pump Using Spill Cut Off Point
Sometimes we want to know how to time the injection pump of a tractor engine when we have not got a manual to tell us how to do it. Fortunately there is another method called “spill cut off point timing” which we can use to time the injection pump. The procedure described below is for the 4 cylinder 23C engine as fitted to the Massey Ferguson 35, but the general process is the same for any engine.
And here’s how to do it……
To time the injection pump when you don’t know any of the marks etc, you need to have the injection pump so that it is connected to the fuel supply and bled off to the injection pump. The 4 pipes to the injectors want to be upright, but not connected to the injectors. The drive to the pump does not want to be connected so that you can turn it by hand. Then turn the injection pump in the correct direction of rotation until the injector pipes all squirt fuel out in turn. Then observing number 1 injection pipe (the pipe that connects to the cylinder closest to the radiator), turn the injection pump until fuel comes out of number 1 pipe and then just does stop flowing (it may take a few revolutions of the pump until you are happy with the position). This is the spill cut-off point for number 1 cylinder. Look at the rotor with the letters on (without moving the pump drive) and see where/which letter is at the marker/groove (on a circlip??). That point will then be the reference to use for setting the injection timing. Next go back to the procedure in the DVD and apply your own observation (where we used the ‘G’ mark).
Next check that the injection pipes are arranged correctly. Bear in mind that the direction of rotation of the injection pump, the required firing order (1,3,4,2) and the consequential arrangement of the injection pipes to facilitate this. ie. That when you turn the injection pump by hand that the fuel comes out of the 4 pipes in the order of 1,3,4,2.
Then connect the injector pipes and try it. (Once it is running!!!!!!!!, try small adjustmens on the pump mounting flange slide to get improvements in running.