Here's a weird one. I've been working my way through literally all the ignition bits, hunting vacuum leaks etc. 

 

Still feel something is not right with the idling on my mk2 (1043cc with Weber and manual choke conversion). So I've finally started on carb adjustment. 

 

Only problem is the idle speed screw wasn't even engaged in the cam! So presumably was having no effect on idle speed until I started adjusting the carbs and screwed it in a bit. 

 

I have a vacuum gauge and can now get it idling OKish by adjusting the mixture. But now the idle speed seems a little too high (tested it to be around 1000-1100 using a cheap induction rev counter). That's about as good as I can get it and I can't adjust any lower even if I wanted too unless I'm missing something. 

 

So what would this mean, is the choke perhaps not properly disengaging and if so how do I adjust?

 

When I pulled the spark plugs they seemed pretty sooty and rich to me too.

It has just occurred to me this could be just the accelerator cable needs adjustment too?

any pics of what you are doing

 

i recall my weber had a screw on a cam that was the fast idle setting ...could you be messing with the wrong thing? 

Could be

Here's a pic, I'm adjusting the screw with the white 'tamper proof' cap (just behind the spring there):

 

 

It does seem to affect the idle speed, but only down to about 1000 rpm for some reason.

what model number is the carb?  

I think it's a 32 TLA with manual choke conversion.

The screw you are adjusting looks like the basic throttle angle stop screw. This shouldn’t need adjusting as it is factory set. The idle speed is set using the big air valve adjusting screw( idle speed boost screw )which is the same method used on the Pierburg 1B3.

 

If you’ve upset the basic throttle plate position you may not get a correct idle speed or it may not be smooth. It will also upset the CO levels..

 

To reset the basic Throttle position on a 32TLA you can try this to get it back somewhere near:

 

With engine off:

 

1) Make sure the choke is fully disengaged and the fast idle screw is not against the fast idle cam.

2) Remove the tamperproof plug from the throttle stop screw.

3) Turn the stop screw outwards until a gap appears between the screw and the stop.

4) Adjust the screw back in until it just contacts the stop.

5) Turn the screw in a further quarter of a turn.

 

You can then reset the idle Speed using the air valve adjusting screw. Note that if you have a working idle speed boost system you need to unplug the electrical connector from the valve solenoid valve on the RH side of the bulkhead. If not you may not get a true idle speed, as the system will increase idle speed automatically if the engine revs drop below 700rpm.

If you have adjusted the idle CO screw then that can be readjusted after you’ve got a decent idle speed. If you  haven’t got access to a gas analyser then best method for adjusting the mixture is to adjust the screw until you get the smoothest idle.

 

Fine adjustment can then be made to the idle speed via the air valve screw.

Edited 25 March, 20224 yr by mk2tastic

Hmmm, after looking at that photo again I think you don’t have the idle speed valve fitted in that carb.What year is your Bready?

 

Is it definitely a Weber 32TLA with manual conversion and not a 32TL that had a manual choke  and no idle speed boost valve?

 

Also, there seems to be a black air pipe not connected to anything by the throttle cable rotary connection. If that is the case, then I suspect that would have been part of the Idle speed boost system. The other end should connect to the solenoid on the Bulkhead that I mentioned in my earlier post.

Edited 25 March, 20224 yr by mk2tastic

Ah OK that's very helpful you could be right about it being a TL. There doesn't seem to be an idle boost valve. That unplugged vacuum pipe is the one that goes to the air filter (I plugged it when running the car and fiddling with the carbs). 

 

OK I will try and adjust it again and might have more luck this time using the right screw!

If memory serves, the Weber carb id should be stamped on the bottom edge of the casting.Not sure exactly which side, I think back, bulkhead side, but without digging my spare 32TLA out of my garage I can’t say for sure. Unless it has an aluminium tag attached to the top like the Pierburg?

 

If it’s a 32TL there a slightly different method given of setting the basic throttle position with the engine running, but to get you somewhere near the 32TLA method should work.

Edited 25 March, 20224 yr by mk2tastic

Thanks for your help again folks. I got it running really nice now using the proper mixture screw on the other side of the carb, then backing off the basic throttle angle screw (one with the tamper proof cap in the pic) until it just touches and fine tuning the idle speed with the one in the square casting. 

 

Mixture must have been way off for a while but it's idling much smoother now.

 

I hope that's the end of my running issues!