Hi Makin Hay,
Paragraph 55 gives the I&T 684 Shop Manual procedure for removal of injection pump involving setting the timing marks and a special tool to pull the injection pump drive gear off the drive shaft, etc,etc.
Now I will give you my method, if you decide to use it it is at your own risk. My method is only good if you repairing the present pump. If you are replacing the pump with a different pump then you have to use the I&T manual procedure of aligning the timing marks before removal of the old pump.
1) Shut off Fuel at tank.
2) Clean everything very well.
3)Remove the rectangular timing cover on the fan side of the pump.
4)With STOP/RUN lever in STOP position crank engine with starter and note the direction of rotation of pump drive gear. If you have to rotate the pump drive shaft, this will be the direction to turn it.
5) Remove Throttle and STOP/RUN control rods.
6)Remove fuel & injector lines at rear of pump and cover both pump and line end with plastic food rap and elastic band to hold in place.
7)Very Important - before loosening any nuts - Scribe a line on pump and mounting surface in at least 2 places.
This will be used to re-align pump when you re-install it. Also scribe a mark between the hub that is held by the 3 cap screws and the pump drive gear.
8)Remove the 3 mounting nuts and washers from pump mounting studs.
9)DO NOT LOOSEN the 3 cap screws on the pump drive gear. 10)Loosen the large nut on the end of the drive shaft until the nut is even with the end of the drive shaft.
11) If you have a friend have him/her hold onto the injection pump, now with a small piece of hardwood or other material that will not damage the drive shaft, drive the shaft rearward. It is a taperred shaft with a woodruff key so shaft should release from drive gear easily, then remove large nut and take pump out the rear.
12) BECAREFUL NOT TO ROTATE PUMP DRIVE SHAFT OR ROTATE ENGINE. If you have to rotate pump drive shaft be sure to always turn it 2 revolutions in the direction that you noted from the drive gear to keep it in time with engine. Reason pump only turns at 1/2 the speed of the engine.
13) Re-install pump with new gasket. Make sure to line up the scribe marks that you made.
14) Reconnect fuel & injector lines but leave the nut loose on 1 line.
15) Reconnect throttle and STOP/RUN control rod. Make sure STOP/RUN is properly adjusted. In STOP position back against plunger and RUN position all the way forward to horsepower adjusting screw.
16)Turn fuel on at the tank.
17) STOP/START/RUN in START position and throttle 1/2 open crank engine and see if it will start.
Caution do not crank starter motor for more than 60 secs at a time and then a cool down period
before cranking again. Engine should start, tighten remaining injector line nut. BECAREFUL NOT to get hit with high pressure fuel from injection lines as the Diesel fuel will penetrate you skin and cause serious injury.
Check for fuel leaks around fuel & injector lines.
18)Check tractor starting ability. If it is harder than normal to start or kicks back on the starter then you should check the injection pump static timing as per I&T Shop manual. Also if it smokes more than normal.