2E3 Pierburg on 1.9dg tickover too high

[SamsBus2012]

Morning all.
After recently changng the vacuum advance on the distributor and also a rogue vacuum tube, the van is running fine, however, once warm the tickver seems a little high. I dont have a rev counter but is definately too high (from a sound level and previous experience perspective anyway). I've tried lowering the tickover using the adjustment screw in the centre rear of the carb body but it wont go any lower. The throttle is returning fully onto it's stop. The spark plugs have a really pale brown/beige residue on them - so is it running a little lean or is that counterintuitive. Any ideas?

[CJH]

I could never get the tickover low enough until I eliminated all the leaks in the vacuum system. In my case I think the biggest improvement came when I removed the vacuum hose that connects to the airbox and put a bung over that spigot. If you've replaced the vacuum advance unit already, check that the choke pull down unit and the second stage throttle unit can both hold a vacuum - if you can suck air through their pipes that's the same as an air leak.

[Ralf85]

You haven't mentioned if you have adjusted the tickover/idle screw on the cam at the end of the cable.

[CJH]

You haven't mentioned if you have adjusted the tickover/idle screw on the cam at the end of the cable.

Is there such a thing? I can't think what you're referring to as 'the cam at the end of the cable'. All the carb adjustments are on the carb itself as far as I'm aware. If there's a cable adjustment I would have thought that's just to make sure there's no slack.

But there's potential for misunderstanding here. Are you (Ralph) referring to the same screw that I assumed Sam was referring to (bottom left in this photo)?


And Sam, was this the screw you meant, or are you perhaps describing the idle mixture screw, which is somewhat inaccessible inside the rear right corner of the carb body (sorry, no photo). If so, that's not the idle speed adjuster, although the revs will drop if you wind it in to reduce the fuel that flows at idle - don't do that though, that's not how to adjust the idle speed, and you'll mess up your idle mixture.

[SamsBus2012]

Sorry away on business so catching up when I can.

I could never get the tickover low enough until I eliminated all the leaks in the vacuum system. In my case I think the biggest improvement came when I removed the vacuum hose that connects to the airbox and put a bung over that spigot. If you've replaced the vacuum advance unit already, check that the choke pull down unit and the second stage throttle unit can both hold a vacuum - if you can suck air through their pipes that's the same as an air leak.

Funny you should say that about the vac pipe to the air box...

https://club8090.co.uk/forum/viewtopic.p ... 5#p8142588" onclick="window.open(this.href);return false;
maybe I should try that.

Also,

...

And Sam, was this the screw you meant, or are you perhaps describing the idle mixture screw, which is somewhat inaccessible inside the rear right corner of the carb body (sorry, no photo). ....

Errr no, I was referring to the long screw with the plastic sleeve that comes out of the back of the carb (ie the side of the carb that points toward the back of the van).
So clearly, I need to look at the screw in your pic.
@ Ralf,.... by the "cam", are you referring to the quadrant that the throttle cable wraps around?

[CJH]

Errr no, I was referring to the long screw with the plastic sleeve that comes out of the back of the carb (ie the side of the carb that points toward the back of the van).
So clearly, I need to look at the screw in your pic.

That's the correct one, and is the one in my photo (which is taken from an unusual angle).