Some comments on the video:

- The lever on the back of the injection pump has nothing to do with fuel output control. All it does, when the throttle is at idle, is push a spring-loaded vibration damper against the fuel rack to smooth idle out. You can remove the control rod that runs to the lever, and let the lever stay down under spring tension, without causing any problems.


- Yes, the governor uses vacuum to limit fuel delivery. Think about towards the end of the video where you are looking into the throttle body at the little venturi that's dedicated to the governor. When the throttle plate is closed more air will be sucked through that little venturi thus creating more vacuum. As you open the throttle less of the intake air will go through the little venturi, thus reducing the amount of vacuum created.

The vacuum signal created in the throttle body acts on a spring-loaded diaphragm inside the injection pump. That diaphragm is connected to the fuel rack. The coiled spring pushes the diaphragm and rack forward to increase fuel output, while the vacuum acts on the diaphragm to pull it and the rack back to limit fuel output.

At idle, while max vacuum is created, the rack is held back to limit fuel output so the engine runs at idle speed. Opening the throttle all the way reduces the vacuum to a minimum, which allows the coil spring to push the diaphragm and fuel rack forward thus delivering max fuel output.

If you remove the throttle plate from the throttle body there will be little-to-no vacuum to hold fuel delivery back and the engine could runaway uncontrolled.


- It does appear that you have the later style glow plugs. You are correct that all you need is 12V to that last plug to power them up. The original system was all manual control, and provided a visual aid for determining how long to glow, in the form of a resistor strip in the dash that glows with the plugs. There was no relay to control the cycle.


- RE testing for vacuum leaks - Yes, pull a vacuum on that line and see if it holds. There are two main causes of leaks in the system; bad diaphragm, and worn and leaky "adjusting shaft" and its bushings (this is the shaft that's controlled by that rod that comes down to the lever from above). A leak could be caused by one or the other, or a combination of the two. A less likely cause of vacuum leak would be a cracked housing.

This thread should shed some light on what's happening inside the back of the pump:
Parts for Pneumatic Governor, OM615 and OM616


- Yes on straightening out the bent lever at the throttle body. You are correct that the one is supposed to move the other.


- So yeah, you can remove both rods that run from the throttle body to the injection pump with no ill effects. When you remove the one that runs down to the lever on the injection pump you're making it so the rack damper stays forward all the time. When you remove the top rod you then lose your idle speed controller. All basic throttle related functions are still intact at this point.