E21 318 y1978 Solex DIDTA idle too fast

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SFerrari
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Posts: 18
Joined: Tue Mar 01, 2022 3:21 pm
My E21(s): 1978 E21 318 carb

E21 318 y1978 Solex DIDTA idle too fast

Post by SFerrari »

Hi,

I come back to you with an issue after a full restoration of my car (including carb : all new seals, ultrasound cleaning.....)
The car is equiped with the Solex 32 DIDTA carb.

The idle is WAYYYY too fast. What ever the settings of idle on main lever, or idle screw or even idle mixture, whatever they are set to what could be the correct position, or if I put them in the lowest position, it still remains so high that my ears are bleeding.
I don't have rpm odometer but it could be close/higer than 2000rpms or so...

What could make the idle so high even with settings set to minimum or even 0 : idle lever fully removed, idle screw fully closed and so is the idle mixture screw. At this stage the car should definitly stall but it goes faster!

So what could it be please ?? Any idea ? The only weak point is the advance ignition/timing which might be uncorrect, could it be the reason that make the engine runing high whatever the basic idle settings are ??

Thanks for your help


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Peter V.
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My E21(s): '82 320/6
Location: Breda, Nederland

Re: E21 318 y1978 Solex DIDTA idle too fast

Post by Peter V. »

* Can you check if the throttle valves are really shut? Also, the second stage?
* The top valve of the automatic choke is completely open?
* Leakage through the bottomgasket of the carb and inletmanifold?
* Believe it or not but sometimes i See that the throttlecable is to tight
Gr Peter V.

.Some say he eats nuts and bolts for breakfast, all we know is he is called the carburetorman.

BMW E21, 1981 320/6 Ascot Grau.
BMW E85, 2004 Z4 2.5i Sterling Grau.
BMW F31, 2017 320dA EDE Luxuryline Mineral Grau.
SFerrari
Newbee
Posts: 18
Joined: Tue Mar 01, 2022 3:21 pm
My E21(s): 1978 E21 318 carb

Re: E21 318 y1978 Solex DIDTA idle too fast

Post by SFerrari »

I really suspect a wrong timing adjustment, altough I did align all marks... pretty strange !! I do have to turn the ignition head by at least one quarter of a full turn to finally see the rpm dropping significantly... and I turn the head clock wize which is even wirder... and eventho the basic idle screws in carb have no effect whatsoever on the rpms... I will borrow my friend's stroboscopic lamp to adjust for precisly ;-)
adatas
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Joined: Thu Oct 20, 2011 1:03 pm

Re: E21 318 y1978 Solex DIDTA idle too fast

Post by adatas »

Hey, did you managed to fix that?

I have somewhat similar issue. After complete rebuild of my SOLEX DIDTA 32/32 carb, it started idling at high rpm.
My first suspect was faulty needle valve which does not close properly and lead to overfueling. But it's working fine.
Then I figured it could be wrong float adjustment = fuel level too high in a float chamber. Tried tweaking it to a level I couldn't even start a motor anymore (doh)
Tweaked it back a little and it starts again now, but as before - RPMs are too high.
Any advise would be welcome.
adatas
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Posts: 2
Joined: Thu Oct 20, 2011 1:03 pm

Re: E21 318 y1978 Solex DIDTA idle too fast

Post by adatas »

Should fuel squirt into a second barrel during cold start? My guess would be no, but I see that's happening.. maybe that's the issue.
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