123 Chassis - 240D problems

My 1977 240D won't sustain a low speed idle. By that I mean that once started, the revs constantly increase until the engine is roaring. The car can only be driven by downshifting the 4 speed manual, forcing
down the engine rpm's while also braking. An ungood condition!
The car also won't shut off. For that I suspect the vacuum diaphragm in the fuel injection pump. Are the problems interrelated?
The vacuum pump seems to be working since the power brakes are normal. There is no locking system so door vacuum lines, etc are non-existent.
From an aftermarket tech manual I see that there are two types of mechanical fuel pumps. One has a mechanical governor, the other type is pneumatic. Should I start my investigation there?
tnx,
Doug
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Look at the simple stuff first.
Check the throttle linkage to ensure it returns to its idle stop screw limit.
Replace the "shut down device" (Vacuum bellows that pulls the fuel rack to OFF when you turn the key to OFF). These cost about $35 on line. Then, it will either be fixed or you know the shut down is excluded from further consideration.
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On Thu, 05 Jul 2007 08:45:13 -0700, "-->> T.G. Lambach <<--" <"T.G. Lambach at NoHamorSpamcomcast.net"> wrote:

Thanks for the hints. I had already checked the external stuff like making sure that the linkage returned to its stop. The engine starts racing WHILE the linkage is at the full stop postion.
I'll order that bellows.
Doug
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