TheSamba.com :: View topic - They say the carb is toast. Your opinions? Help!

Mon Nov 17, 2008 8:16 am

We have a 1974 Westy. A P.O. took off the dual carbs and put on a singel Weber progressive with a dual port intake pipes.

The bus will not idle and stalls out even with some major accelorator coaching.

It seems to run fine, if and when you can it up past 30 miles an hour.

We had a local VW shop, who specializes in vintage VW's, tell us our single Weber progressive 32-36 carb is toast. They said that two of cylinders are not getting gas. The owner was not in at that time of calling, but will call me back.

Are they pulling my leg or does this sound plausible.

BTW, Last week we pulled the carb apart, cleaned it out including the jets and put in a new rebuild kit. This did not make any difference.

And we replaced all the vacuum lines. Got the info from Ratwell

Mon Nov 17, 2008 8:25 am

I would start looking for a good set of dual carbs for this thing. Get the whole set up if possible and plan on rebuilding them.

Spending money on a weber progressive is a lot like re-arranging the deck furniture on the Titanic. Limited long term value.

Mon Nov 17, 2008 8:27 am

Randy in Maine wrote:
Spending money on a weber progressive is a lot like re-arranging the deck furniture on the Titanic. Limited long term value.

Randy... That is an awesome line. :lol:

Mon Nov 17, 2008 8:44 am

2 cylinders not getting gas? that's not the way a prog manifold works, I'll bet the connector boots on the manifold are torn or cracked.

Mon Nov 17, 2008 8:58 am

X2 with Busdaddy, you are sucking in air somewhere.

Mon Nov 17, 2008 9:08 am

I would replace the manifold boots as well, using the red silicone boots. I've found the black rubber ones to last a very short time and have had good luck with the red silicone ones, and they're cheap.

If you want to replace the Weber with the original setup, I have a complete set of dual carbs off of a '74 including all of the linkages, balance tube, etc, etc. They would need to be rebuilt for sure but in the long run you would be better off than with the Weber.

Tue Nov 18, 2008 6:42 pm

Thanks for the info guys. Much appreciated.

I had a look at the manifold boots, and they appear to be OK. But I know what you are going to say. Replace them anyways, because you see what you can't see.

At the same time I'll replace the manifold gaskets.

The above will be an interim fix, hopefully. We are definately going to install a set of dual carbs. I know there are some in the classifieds and I should probably email Keifernet.

p.s. VDubTech, I sent you a PM the other day.

Tue Nov 18, 2008 6:53 pm

Before you get too far into this do yourself a favor and ensure the mechanicals of the engine are good before sinking money into sub-systems.

1.) Adjust valves. You have solid lifters - not too big a problem.
2.) Disconect fuel pump.
3.) Run a compression check to ensure good compression on all cylinders.

If two cylinders are NOT getting gas - it could be a compression issue!

Also - be sure your ignition system is in good shape. Check your points and dwell. They say most carb issues are really timing issues.

THEN go from there.

A simple way (without doing a compression check) is to turn the engine over with the starter and listen for any "fast" turns --- ie - an uneven turn on the engine while trying to start - as if it gets quicker on a certain cylinder or two.

But best bet is the compression check. If your compression is off by more than 10% on any given cylinder, you can bet you'll feel it when you try to run it!

Good luck!

Tue Nov 18, 2008 7:09 pm

Why don't you just start her up and pull each wire in turn off the distributor cap. For some reason two plugs apparently are not firing or at least the cylinders they are in aren't carrying their fair share of the load. Once you have identified which cylinders are loafing, try and figure out why. With a center mount carb unless you have a vacuum leak in the boots or manifold gaskets you will get the same fuel mix to each and every cylinder. If the carb isn't right it should affect all cylinders pretty much the same amount.

Wed Nov 19, 2008 5:42 am

Don't know what you have for a distributor, but you will find a huge improvement with the Bosch 009, with an electronic ignition module. Use the thick intake manifold gaskets, that originally came with your set-up. Those stock Solex carbs are so out of date, read, OBSOLETE! it's not even funny. I have been down that road too many times. Good Luck and keep us posted on your results.

Wed Nov 19, 2008 8:01 am

nodrenim wrote: Those stock Solex carbs are so out of date, read, OBSOLETE!
I never new that we were supposed to be au courant.

Sun Dec 07, 2008 6:19 pm

Thanks so much for all your advice. I finally got around to troubleshooting the problem and was waiting for some parts to be shipped.

The problem was that the intake manifold gaskets were pretty well non-existent. I took off the intake manifolds along with the spacer. the gasket was less than paper thin and had to be scraped off of the spacer.

So I installed new gaskets on both sides of the spacer complete with "Form-a-Seal" gasket gunk. It made a world of difference. Started up fairly quickly and idled perfectly.

We also went ahead and changed out all the ignition components, plugs, wires, coil, dist cap, etc. etc.

It is now backfiring periodically. Does that mean it needs the timing done now?

It was recommended to time it statically, as I have a vac advance on the dizzy.

Sun Dec 07, 2008 6:31 pm

Carburated engines used four metal gaskets between the manifold and the heads to move more heat up into the manifold. It doesn't make a huge difference with an icy progressive, but it will make some.

Set your timing to 28°BTDC hoses off at full mechanical advance ~3000-3500 rpms.