DCOE throttle sticking

[hunters2002]

i put a weber bar linkage on some 40 DCOE and under some normal accleration the throttle will just acclerate on its own. i've already checked and its not getting caught up on anything.anyone have any ideas

[Zenon]

Make sure your engine mounts are in good shape and the engine is not able to twist too much on acceleration. With a stock-style rod-type linkage, movement of the motor can open/close the throttle(s). If you also notice the car bucks when you are trying to drive slowly (like during rush hour) with very small throttle openings, that could be your problem as well.

That's a big argument in favour of a cable linkage - properly done, with the pedal-end's reaction bracket mounted to the body (NOT the engine), the throttle position will not be affected at all by engine movement.

There is also a serious safety issue: With a rod linkage (even the stock carb setup), a broken engine mount can let the engine twist enough to hit wide-open throttle and can jam it there - pretty scary.

regards,

Zenon

[dapbmw]

or your gas pedal bushing is shot and the spring is rusted....lube the gas pedal arm in the pedal box with silicone or lithium based products.

[ash00]

I'm experiencing the same problem, and this is the 3rd time. As if I didn't learn the first two times...

But my problems were always bent throttle shafts (where the butterfly valves attach) The first butterfly valve would be pushed a bit, causing it to bind up with the casing- which let more air into that cylinder- hence a sticking RPM.

I have the top pull system with a cable linkage from Ireland. Between the carbs are a linkage to couple the two carbs mated to rods ends to the top pull setup. My first problem was the nut backing off on the bolt going through the rod ends, causing that shaft to be loose.

I'm going to run a few tests:

-run parallels on the casing of the carbs and the intake manifold. My first assumption is either a warped casing or a warped intake. If its the intake- first off try to figure out HOW it became warped, and then prop it on a mill and surface both sides of it. Yuck.

-If its the carbs, I'm screwed. Can't seem to find another "casing" alone. Even at Pierce manifolds or whatever.

-build up more motivation to go EFI!

[Chris_B]

One other minor possibility is the nut on the throttle shaft... don't know if you had to mess with this to install your linkage, but if you over tighten it, the throttle may bind.

[ash00]

True-

you'd also feel some resistance since you are tensioning the rod if you tighten it up too much. You can get a feel for it when you turn the shaft. When you install it though, there needs to be enough pressure on the washer on the sides to avoid vacuum leaks.

[BigDog]

I like the looks of the traditional bar style DCOE linkage setup, but there are better choices for performance, adjustability, and reliability.

Look at it this way, you only physically touch your car in a few places, you want that interaction to be as good as you can afford to make it. The shifter, steering wheel and pedals!

For the DCOE most people seem to think the peirce manifolds topmount linkage combined with a cable setup is the best way to go. Personally, I agree!!! It's easy to adjust, gives great pedal feel, and is VERY reliable.

It's not sexy, it's infact rather ugly praying mantis kinda thing on top of one of your carbs, but it's not to be beat for reliability and function.

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BigDog

'76 2002 Weber DCOE 40s