And here are some pictures that I have posted in the past.
In the first one you remove the safety wire (cutting or breaking), remove the two screws and the keeper on the rod. Then you slide out the Fuel Control Unit.
MAKE SURE you retrieve the Plunger Sleeve Pin. And don't loose it.
The second picture is a diagram of how the IP Hydralic Head functions. It is looking from the front of the IP.
The dark lines are the fuel path.
Here is a "simplified" explaination.
1. The Fuel Control Unit (kill switch) moves up and down, the Plunger Sleeve Pin swivels in the groove on the Plunger Sleeve.
2.When the Sleeve is UP, the fuel will flow into the Spill Passage. When it is DOWN no fuel will flow and the engine stops.
3. When the engine is turning, the camshaft, quill shaft and associated items turn and move
4. When the Plunger Drive Gear moves it moves the Fuel Plunger UP and DOWN
5. While the plunger is going up and down, a gear inside the HH is moving in a circle, moving from injector line to injector line. The pressure of the plungler is building preassure inside each of the injector lines.
6.When the cylinder is ready to fire and the preassure is high enough, the injector will "POP" open and spray the fuel into the cylinder. We Have Fire!!!
SO.....with all that said, If the Plunger Sleeve is gummed up and doesn't move freely, the truck will not start or will run at full throttle.
And here are a couple of threads talking about the same issue.
http://www.steelsoldiers.com/deuce/41122-injection-pump-repair.html
http://www.steelsoldiers.com/deuce/29359-m35a2c-clogged-fuel-system.html