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Fri Dec 27, 2002 1:30 pm

I recently bought a 1972 Beetle, 1600 dual port motor, Bocar 34 PICT carb (looks new) and standard vacuum advance distributor. (the last bug I worked on was a 1964,1200 single port, about 15 years ago, so I have forgotten most of what I never knew!) On the left hand intake manifold there is a vacuum line fitting that was plugged off when I bought the car. It came with an after market chrome paper-type air cleaner on the car. With the vacuum line plugged off the car will not idle at all, but with it open it runs pretty "normally". But I cannot believe that the intake manifold should be sucking that much air below the carb. I have looked around everywhere on the Internet for information about where that vacuum line is supposed to hook-up, to no avail. The car runs strong on the freeway with that line plugged, but it will not idle at stop lights at all. Please advise on how to solve problem. I just want to keep the car running until I can afford a pair of Webber 40's and a new ignition set-up. Thank you for your help. Beetle

Fri Dec 27, 2002 6:24 pm

I have that same vacuum line port on the left manifold as well and have never known its purpose, however, mine is plugged and runs fine that way or without the plug. Sorry, I can't help you, but I would like to know what should be hooked up here.

Sat Dec 28, 2002 6:55 am

Its for the de-acceleration valve mounted in the upper left hand corner of the firewall above the engine. The valve, along with a disphram mounted to the carb, is used for smog purposes to keep the throttle slightly open for a period of time when you let off the accelerator. My replacement Bocar did not have the neccessary fittings for the diaphram so I just plugged everything up with no other problems.
I have heard of people having problems with the Bocar, especially bad floats, even when new. Make sure its adjusted correctly or replace it with one from a Solex.

Sat Dec 28, 2002 6:59 am

Whoops! Should read upper left hand side of the engine compartment.