Missing pipe and carb screw

[MagicWagon]

Looking over the engine on my "new" 1983 2.0L Aircooled Devon, I noticed 2 things.
1. There was a screw missing on the left hand carb. I found it in the debris on top of the engine tinware and refitted it, but I'm not sure what it is and how far it should be screwed in.
Some googling suggested it may be the venturi screw and some more suggested it should be 2 1/2 turns out. However, the one on the other side, whatever it is, is screwed all the way in.
Here's a picture. Any ideas ?


2. I noticed there was a pipe missing on the distributor and the airbox. Not sure if the airbox is meant to connect to this elbow on the distributor. I also found a disconnected pipe at the back of the engine in the tinware debris.
Here's a picture of the "missing" pipe connections, and the pipe I found. Can anyone tell me what connects to what, or what am I missing.


Thanks

[bigherb]

Yes it is the venturi screw, it locks the venturi in place, just screwed up tight (don't over tighten it).

The vacuum pipework should look like this.

[MagicWagon]

That's brilliant.
I'll try and get that pipe sorted tomorrow.
What does that missing pipe to the distributor do anyway ?
What issues would it have caused not being there ?
Cheers.

[bigherb]

What does that missing pipe to the distributor do anyway ?
What issues would it have caused not being there ?
Cheers.

It retards the timing to 5 deg ATDC at idle and retards the timing on a closed throttle to help with emissions and smoother idling. Won't have done any harm with it disconnected. You will have to readjust the idle speed with it connected, (if it doesn't alter the idling speed then the retard diaphragm in the vac unit has split), remove the plugs from the digital idling stabiliser if still fitted and connect them together adjust the idle speed to 850 +/- 50 rpm then reconnect the idling plugs.

[MagicWagon]

Thanks to all. I have bodged something together to connect the pipes back up and it does indeed seem to run a little better.
I have been unable to find the correct pipes to buy. I'd like to replace all these "thin" (vacuum ?) pipes so if anyone knows where I can get them I would be grateful.

[bigherb]

I use 3mm id silicone vacuum hose and 4 mm od nylon pipe.
https://www.ebay.co.uk/itm/Silicone-Vac ... 0cL1Ykw4_A" onclick="window.open(this.href);return false;

https://www.ebay.co.uk/itm/NYLON-PNEUMA ... uz5oieGSCw" onclick="window.open(this.href);return false;