My 300D idles at around 600 RPM. In the warmer months this is not a problem. In colder temps, the engine stalls upon cold start. Unlike my 240D, which has a manual idle adj knob, the 300D has no such provisions (except my foot). What were the Mercedes engineers thinking?

The 300D throttle control is pretty complicated with so many linkages. Where is the correct place to adjust it?

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

It's on the IP. Look at the where the linkage hooks to the IP, there's a locknut/bolt that can control the idle position of the linkage.

are you talking about the throttle stop? It runs parallel to the pump and limits the motion of the entire linkage assembly?

this is not to be adjusted.

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Between the IP and engine block you'll find a slotted bolt with a lock nut at the bottom of it. Loosen the lock nut and rotate the slotted bolt to raise or lower the idle RPM. Then nighten the lock nut.

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There are two 'throttle' stops, one for full power and one for idle. The idle stop can be adjusted as biodiesel300TD describes

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1979 240D- 316K miles - VGT Turbo, Intercooler, Stick Shift, Many Other Mods - Daily Driver

1982 300SD - 232K miles - Wife's Daily Driver

1986 560SL - Wife's red speed machine

gotcha. The wording threw me off, I was being cautious. (despite my poor terminology)

BioD's instructions were very clear, I left it at that.

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This needs to be rephrased into "cajole the locknut from resisting". The casting ear that supports the threaded rod/locknut isn't strong enough to take unlimited breakaway torque on the locknut. The result of overtorque is a complete disaster..........replacement IP.

Is subject adjustment a round shaft with a slot that takes a flat bladed screwdriver which faces upward and require a deep socket to undo the locknut? After my engine warms up, it idles at 750 RPM. Is that too low or about right? I think I will leave it alone if not too low and just install a choke cable for a manual idle adjust. Anyone done that?

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Thats the one. 750 is right about where you want it.

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I haven't done that, but I did raise my idle to about 850 to 900 RPM at warm idle. In the summer in Phoenix, running the AC full blast while in gear with an Automatic makes the engine run a bit cooler in city traffic!

For putting in an idle adjust knob, I believe you would have to swap out the stop lever from a model with the idle adjust cable, and then you'll have to drill a hole in your dash to put the knob into. I'm not sure if the stop lever from a older model will work with the newer model's linkages.

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