Williams air throttles are very touchy when trying trying to control the smoke factor on DD the pedal has to match the control cylinder springs the linkage has to be just right once all the stars are inline they work
Eagles are the worst because you have to use a universal controller because there is not enough room on the top of the governor to use the DD controller
Thanks, Clifford. That's a good thing to know. I am not sure exactly what I have -- plus, it's located on a fuel pump for a six-cylinder four-stroke diesel with a control pivot arm that I fabricated. I bought these parts used from "Nimco" when they were in the business of selling used parts and there was no info with them -- I was amazed when I clicked the part numbers stamped on them into Google and the tech specs from Williams popped up. Unfortunately, those tech specs don't tell exactly what vehicles/engines etc. that the paired assemblies were made for.
However, the system works very quickly and cleanly. I haven't noticed any problems with the system at all, except I have 100% of control arm movement at the fuel injection pump when the pedal has been pressed about 30% of the way. After that, it doesn't matter -- until you let off the pedal, you keep 100%. It never feel like a problem; when you want to go, you press the pedal, when you want to slow down, you let off the pedal -- but, as I said, it's touchy feeling. And it will probably feel more comfortable to drive if the touchiness if reduced.
I think that what i need to do is change the control arm geometry to better make use of the pushrod extension from the air engine cylinder and drop the pressure. I'm not sure that running 120 or so pounds of pressure makes much difference to the response but it seems likely that lowering the pressure is good for the long-term reliability of the system and it just might help with the issues of the touchiness.