B-250 Injection Pump

If so, there is a throttle butterfly above the intake manifold, and one of the lines connects above the butterfly, and one below.

At startup, those lines, AND the diaphragm governor will not have ANYTHING to do with injecting fuel, as a light spring will have pushed the "rack" in the injection pump to the full-fuel "start" position.

After startup, there is a pressure differential across that throttle butterfly that varies with throttle position, engine speed, and load, and acts on the diaphragm in the IP, controling engine speed.

Has the machine sat unused for a long time, so the "rack" may be stuck, or the plungers in the pump may be sticky, and not returning, to take on a fresh charge of fuel?

Or, has it been running recently, and been run out of fuel, and needs to be "bled" of air?

Previous reply about the pressure differential diaphram is correct.

JB2

On those, when you pull the "kill" cable, you can feel the "rack" inside the pump move from the "full-fuel" start position, to the "fuel cut-off" position. How is the "kill" or shutdown set up on your's set up? You should be able to feel the same "load" on the "kill" button, as the "rack" slides back and forth.

Years ago, I got a Ford Major Diesel that had sat for a long time. The injection plungers were so sticky they would not return. I partially dis-assembled the pump, and freed the plungers with carb cleaner and/or WD-40. It's been over 20 years, and I don't recall all the details, but the tractor is still in running order today.

Also, the diaphragm will move back and forth, along with the "rack".

A tear in the diaphragm will affect the functioning of the governor, but NOT starting.