I purchased brand new weber 44 idf carbs from redline weber recently. I set everything equally between all barrels. I set the idle stop at 1/2 turn on both carbs. The engine started right up. I disconnected the linkage. Checked the air flow with a snail. Equal readings on cyl 1,2. Cyl 3 was pulling in so much air it was off the chart and cyl 4 was barely getting any air. I backed off the idle stop completely and I am still getting a huge amount of air in cyl 3 and almost none in cyl 4.

I took the carb off and visually inspected. Everything appears normal. Both butterflies appear closed.

FYI- I am certain that this is not a valve or cylinder problem. Everything was fine with my previous setup.


Any ideas?

Temporarily swap the carbs right & left. If the problem is still on #3, the valve train is suspect.

there is a balance adjustment screw between barrels on the webers.

Just swapped the carbs. The problem moved with the carb.

Tried adjusting the balance adjustment screw. The difference was so extreme that it would balance. It helped but did not get close enough.

Dang, Steve. You have a fecal touch with carbs.

Not the first time I've seen new webers with throttle butterfly problems. If you pull that carb off, and hold it up to the light, I bet you'll see a HUGE gap between the throttle plate and the bore.

You can try loosening the screws that lock the plate to the throttle shaft and see if you can get them to sit better.

Oh come on, give me the credit I deserve. I have a fecal touch with everything.

That's exactly what it sounds like. One is aligned, and the other is not.

by balance adj you mean air bypass screws right? did you try closing all of them? there is no reason for the plates to be misaligned. mblizzard had issues with his brand spankin' new carbs. redline. send them back. or screw around with them for a month or so and they might work. or not.

k

I agree again. Didn't think of that. Make sure all 4 bypass screws (the ones furthest to the outsides of the carbs) are completely closed before doing anything else.

Bad manufacturing seems to be a very good reason.

I bet you got the set that I sent back to Redline! They never would work for me. Check the floats and see if they are stained or flaking off small pieces of the float. If they are send them back because there was something wrong with those carbs that I just could not make work. I tried a huge number of suggestions from Redline and the members here and the carbs just would not work! If Weber and or Redline is sending out carbs that you have to fix their manufacturing flaws is that something you really want to do?

By the time I was done, I wished I had just purchased a known used set. I had another $250 in jets and Venturi's and a whole lot of time invested before I sent them back.

Regardless of what Redline says, 36mm Venturi's are too large in the 44s for our engines. When I went to 28s on the second set they began to work well.

PM me if you want the details of my experience.

This isn't necessarily abnormal. Close all the bleed screws and find the cylinder pulling the most air. Bring all the other barrels up to it then finalize your balancing left and right. This is a bit of an art, but really a 2 banana job.

Note: Everything else - especially valves need to be perfect before you do this. You should only need to do this once.

that is NOT a good nor a rational reason mark. jake quit selling NEW webers for a good reason.

to add to my post. closing all of the by-pass screws and measuring the flow on each throat helps you find a baseline. you then have to bring the highest ones down to the lowest. not to exceed the max # of turns out (by passing the venturi) specified in thomlinson's weber manual.

It's just the opposite. With all the bleed screws closed you have to bring all the barrels up to the highest one.

One of the problems is that I cannot reduce the amount of air flow in the highest cylinder even if I back off the idle set screw. If I bring up the other cylinders o match the highest cylinder, I would idle at around 2000.

Now that... Is a problem. That sounds like a bad throttle plate or bent shaft. If these are new you need to work to return them. If not you can either examine the problem and fix it yourself (it's really not rocket science) or send them to Blackline (they bought ACE):

http://www.thesamba.com/vw/classifieds/detail.php?id=1453210

So you've already verified that they're all closed (gently bottomed out)?

I think Mike (Blizzard's) scenario is really likely. You might have gotten his messed up set.

1) Verify all air BYPASS screws are bottomed
2) See if it makes a difference. If not ->

3) Pull the carb off again
4) Use McMark's flashlight in the bores trick to make sure both butterflies close correctly. If not, back off the throttle shaft screws and realign them.

5) If still problems, send them back to Redline as Mblizzard did.

You can't really see if the throttle plates are closing with the carbs on the engine. You need a light on one end and your eyeball on the other.

you need to be very careful loosening those screws.
They are very hard to get loose (if still factory).
It is too easy to apply too much pressure and bend the shaft.

You can back-up the shaft to keep it from bending but then you need to remove the venturis so you can get a block of wood or something in there.

Stu

for heavens sake. how in the hell, with all 4 by-pass screws closed, do you bring the lowest ones up? backing the screws OUT routes the air flow around, BY-PASSING, the throttle plates and reducing the flow thru the venturi. YOU'VE got it backwards. you back the HIGHEST flowing carb bore(s) screws OUT to match the lowest flowing. again, not to exceed the maximum # of turns recommended. go to far and you lean that cyl(s) out.

Sorry you're the one that's backwards. All air coming into the engine flows through the ventri, so no matter if the throttle plate is opening, or the air-bypass screw is backing out, that air is flowing through the snail and reading higher.

NOPE! It's does bypass the throttle plate, but it's still flowing through the venturi. Air entering the 'bypass chamber' comes from the main airflow. There isn't a separate air inlet for the bypass. With regards to airflow, backing out the bypass screw is essentially the same as opening the throttle plate.

This was a common issue with the "Genuine" Webers in 2008 when I stopped using them. The throttle shafts were twisted right out of the factory among other issues.

Too many people buy the name expecting them to be the way they always were before. Not the case.

I found a way to fix my problem. Return the carbs and go back to my old system!!!!

UPDATE-

The issue appears to be that the throttle shaft on on carb is slightly bent.

Also- I found that the secondary venturi's were installed upside down from the factory!!!! WTF!!! I had just taken them out of the boxes when I noticed that they were opposite to my other weber 44 idf's. I thought that my old ones were messed up. It turns out that the new webers are. How could they make such a stupid mistake.

They realized that because of their name reputation they can make just as much money without paying attention to little things like 'being correct'.