Rebuld Weber IDF 40 15 or sell and start new ?

[nelsonj]

Ok - I picked up a used dual carb manifold for my 1800 and on it are two old Weber IDF 40s.
The markings on both carbs look like they say "IDF 40 15". These carbs are also stamped "Italy".
Both carbs are old, one is in rougher shape (looks like it was exposed to water and shows some mild rust down the pipe) and I will have to see if with WD40 I can get both carbs to rotate. (One seems fine, the other not so...)

Q1: I understand the Euro versions got IDF 40 13/15. Correct?
Q2: Both my carbs look like they are 40 15 - is that normal?
Q3: What is the difference between these carbs and modern IDFs? Are these better or worse?
Q4: Will a modern IDF rebuild kit work for these carbs?
Q5: If I can only "save" one carb, can I replace the other with a new IDF or is an unmatched pair a really bad idea...

Finally - is it worth even trying to rebuild these or should I just sell them as-is, take the cash and spend it on new Weber or EMPI carbs?

Let the opinions, thoughts and "what-id-do's" begin....

Thanks guys and gals!

[So Cal Mark]

the new series carbs may have difficulty fitting your old manifold. The throttle shafts are longer and the spacing between carbs is about 20mm wider. I've modified new carbs to fit the older manifolds, so it can be done but it doesn't leave much of the throttle shaft threads on the end. Measure the distance between the mounting bolts.

[Daniel]

Q3: What is the difference between these carbs and modern IDFs? Are these better or worse?
Q4: Will a modern IDF rebuild kit work for these carbs?
Q5: If I can only "save" one carb, can I replace the other with a new IDF or is an unmatched pair a really bad idea...

Hi Nelson

The Newer IDFs are better there are some differences between the 2 designs i've never done a side by side comparison
to judge them but i wouldn't mix match Carbs i'm sure you'll run into plenty of issues then you want everything as square
as possible when doing dual carbs that mains perfectly matched !

I would clean them up as best as possible and place them on Ebay take that cash buy a brand new set of Carbs ! just
what i would do if you want to make these work i am sure its fine to do so .

[Daniel]

The throttle shafts are longer and the spacing between carbs is about 20mm wider. I've modified new carbs to fit the older manifolds, so it can be done but it doesn't leave much of the throttle shaft threads on the end

What Mark is talking about here is shorting down the shafts on the inner ends where both carbs meet i've been
doing this since i started playing with fiats it's not very hard to do just be sure to keep the threads nice and
clean .

[mdrburchette]

Your main concern with your carbs is if the throttle shafts work the butterflies freely. If you have a bent shaft, that's not good. I would also check the bearing the shaft rides in since it's a bear to get the shaft out and you could damage it while removing it to replace the bearing.
As for the old vs new, I have heard the new style may not be the best since Weber had stopped making them for a time and a Chinese company picked up building them. There were problems with these Webers. The early ones are what everyone is looking for. I don't know what the 13/15 or 10/11 numbers refer to on the Webers, but I compare the two you have to see if they are exactly the same or if they are mirror images of each other. It could be someone changed the linkage to run two of the same carb side by side. Like I said, I don't know the difference, so there may not be a problem doing this. do you have any pics of your carbs?

[majicwrench]

There is almost nothing on an old carb that cannot be repaired, unless it is physically damaged, like smashed. Rust, corrosion, can clean up easy enough. I would rebuild old carbs in a heartbeat, they already fit manifold, match.
Although I have no experience with the new carbs, I would doubt that they are really better units.
Keith

[So Cal Mark]

I've put on several sets of the new 70 series carbs and they work just fine.

[131]

I would rebuild old carbs in a heartbeat

Ditto! Unless the castings are broken or cracked, everything else is replaceable. I doubt you'll have too many people asking if they should rebuild an Empi in 40 years time.

[kmead]

The numbers refer to which side the actuator is on the two carbs. As the carb linkage pulls from the center both carbs need to have their bracketry for actuation in the middle. The one on the left side has the actuation on the right and the one on the right has it on the left. The 13 is the left one as I recall and the 15 is on the right. The early cars has 10/11s as I recall.

No I don't know what the difference is.

[nelsonj]

Update: I cleaned up the carbs, and they are in fact 13 and 15 - Just as the previous post indicates. The linkage for the two carbs is joined in the middle.

I am losing confidence in my ability to rebuild one of the carbs. It appears that the butterfly is basically rusted to the venturi. My guess is that water got in from the top and stayed there a while. The carbs are "mated" right now, so I can only get a slight bit of movement from the "good" carb since the "bad" carb won't budge.

Exterior's are in very good shape - they seem to have choke devices that move freely. The pump seem to move freely, and all the parts (save air cleaners) are there. The few adjustments screws I tested seemed to move freely, but I didn't try all.

Given the rust-shut condition though of the "bad" carb I am starting to lose my nerve...I guess the next step is to un-mate them, take them off the manifold and see if I can loosen up the butterfly's on the bad carb (without bending its shaft). Don't think I will have time for this project until Sunday at the earliest...

No rush - my current 32/36 is brand new and working great.

[So Cal Mark]

"I doubt you'll have too many people asking if they should rebuild an Empi in 40 years time."

Interesting statement. EMPI is building and selling Webers under license from Weber. The only difference in the EMPI version is the lack of the big W on the casting. All of the same parts are used and both versions are built in the same factory. The only difference is the price. If you want to spend a lot more money to get the W, more power to ya'

[kmead]

To get them cleaned up they need to be removed from the manifold. I would start off by tanking them for a week after taking them apart as much as you can (buy a gallon of parts cleaner and a strainer). Never try to force the parts as you will just do more damage. Taking some time will reduce the breakage of somewhat difficult to replace parts.

Clearly if they have been exposed to water there will be damage and lots of dirt etc in all the wrong places so the first thing is to get it cleaned out.

[mdrburchette]

You can get a gallon can of carb cleaner at NAPA that comes with the strainer. When you try removing the carbs from the intake, they will probably be stuck. I use a rubber mallet. to tap the parts to break them loose. You may get more movement out of the linkage if you spray some carb cleaner on the area before trying to disassemble them.

[majicwrench]

That stuck throttle will free up. Soak it, tap it, be nice, it will come loose.

[131]

The only difference in the EMPI version is the lack of the big W on the casting.

I recently installed an EMPI on a blokes Suzuki 4wd, the quality of castings and linkages was nowhere near as good as an old Italian Weber. I'd rebuild an Italian Weber every time.