Unusual Weber 40 Problem

[Sweetheart912]

Here's one for the books on the IDF40's. I have set MANNNNY a pair of these up over the years and NEVER had so much trouble setting up as this pair I had for my 68. The main problem was that 3-4 was always running rich & when shut off dumped gas down the throat & leaked all around. I KNOW I was setting them up right ...floats at 10 & 32.5, pump arm correct, etc etc.

After taking the carbs off for the second time, with fuel still in bowls, I had the 3-4 side carb sitting on a coffee can for "observation" while I was squeezing my boys trying to discern the problem. I noticed a large drip of gas drop out of the throat. Huh? Looking down the throat, it seemed like gas was appearing out of nowhere on the middle of the carb throat by the fuel bowl. Wiped it off and it appeared as a blob spreading out then forming a drop. There was a casting fault in the carb body that finally made itself known. Couldn't see it with the eye but under a magnifier a pinhead hole in a casting crack/flash was weeping gas. Under pressure it pushed gas out faster - obviously. CRAP.

I took that thing apart & threw the body as far as I could down the back yard (pretty long distance, eh Jerome?). Maybe a raccoon will take it for tradin' material....boy is he screwing the next raccoon. Anyhow, bought a single parts IDF on a VW site for $35. Stripped it to bare body, cleaned, inspected, then put it all back together with parts from the orig on the "new body", set floats, put the carbs on & it was perfecto. After warming up, I set mixture, barely 1/4 turn on screws, & it is big happy.....just like Webers are supposed to be.

In all my years that was a FIRST. I just thought I'd pass this on in case anyone has a 40IDF displaying similar problems. Check for a casting leak before you give up. Best regards, George

[WFBowen]

George:
Very interesting post. I recently sold a pair of 40's from an extra good running motor I had (carbs were known to be good.) A couple of knowledgeable Ebayers asked me during the auction to check the body casting for "made in Italy", which this set was.
Might be interesting to see any casting identification differences between the one you bought and the one you chucked down the yard. Also, if anyone else has bought a "new" set recently (not old NOS, but recently cast units) to see exactly what the markings on the body might reveal, i.e. Brazil/China, etc. Also, I rebuilt my 40's about 6 mo. ago with "genuine" Weber kits. After lots of flooding, turned out the new needle valve was bad. I'm certainly no Weber expert, but I've had them on various cars since the 60's & trusted any genuine Weber part to be absolutely top-notch in quailty. Not so anymore.
Thanks for the post.
Bill.

[Jerome Ryals]

Long as it didn't bounce off a tree and hit one of your cars, hope you are doing well.

[lapuwali]

Most non-Italian Webers are made in Spain, not Brazil or China. I believe ALL of them are now made there, not Italy. Point of manufacture is also not a fully reliable indicator of quality, either. I've seen Italian-made Webers with bad castings, and perfect Spanish made ones, as well as reverse examples of each.

[Sweetheart912]

Interesting replies, the bad carb casting was Italian, the used replacement that turned out to be fine was of Spanish origin.

This was a very frustrating troubleshoot- rounded up all the usual supects and replaced with new or known good used-like the needle & seat etc.& still same problem. So much for assuming casting reliability.

I agree Bill, more years ago than I care to admit, when you got Porsche parts with OE purple & white stickers etc etc I seldom had a problem. Within that past 3-4 years I noticed parts, especially aftermarket suppliers (and some "OEM" products) not worth a hoot! Man, I put on a new set of Bosch plug wires and TWO...yes TWO were BAD. The vendor gladly exchanged but that is not the point.

We used say parts is parts.....BUT NOW, IMHO parts ain't parts anymore....can't assume any more that just because something is new, it implies quality, or passed a rigorous test or inspection. After the recent lessons provided by Weber & Bosch, I will just about bench check everything "new".....I like to put things on only once.

I suggest all do it yourselfers, like me, be a little suspicious of a new part until you check it out. You may be installing a problem, not fixing what you set out to fix. You can be chasing your tail trying to fix something not broken by assuming a new part is new & just fine.

Take care, George