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Discussion Starter #1
Hi all.
I just got my mechanic who sevices my other car to change my oil etc on my 33, he reckons the carbies are overfueling and not running properly with alot of carbon build up in the air filter box. (My mechanic doesnt want to fiddle around with the twin carbies.) Sometimes when idling even when the engine is warm the revs will die off and stall. I have also noticed a little bit of fuel or oil that must drip down from the carbies onto the cams in the engine bay, its not alot just a little that builds up over time. Over a year ago when i took the car to ciliberties for a service they said to stop that the carbies would need to be overhauled but its nothing really to worry about.

The car smells very rich but i think this is normal? The car generally doesnt idle well, she idles to low.
When driving the carbies run well with no hicups.
I was just wondering what everybody thought on this, if my carbies need a good tune up or overhauled? Does anyone know the cost of an overhaul? Does anyone know a good place for a tune up in Perth, i live in Mandurah.

Cheers!
 

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Sounds a bit like the idle circuit could be running too rich. You said that it runs fine, but can drop revs and die when idling, this sounds like its too rich to me, and not enough air. I would check to see how much the mixture screws are turned out, should be about 2.5 turns for each one. A good tune by yourself or someone who knows webers would probably help greatly.
Rebuild kits are around the $40 - $50 dollar mark for each carby and you can save money if you do it yourself, if not a good repair shop should do them for around $300ish all set up I would say, perhaps a bit more. But try and get a tune to see if it helps first.
 

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Discussion Starter #3
Hi
Thanks for your info, yes the car drives fine she just doesnt seem to tickover very well. Is it ease to adjust the mixture screws, i might give it a go myself. I dont really know an awful lot about tuning carbs. I did try turning up the idle screws a little on each carby, but doesnt seem to have helped. I reckon they are running too rich like you said. Maybe if you have time you can explain how i do the mixture adjustment and what screw it is.
The car is still at the paint shop getting a new bumper and fender :)
Cheers
 

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yes, too rich. before you mess to much id check your plugs to see if you are getting an even built up- could be only one of your carbs is too rich- and if all adjustments look the same, then id check the floats and pin valves- if your pin valves are clogged up they may be getting stuck and letting in way too much gas.- and if your float is bent or otherwise adjusted wrong, again- too much gas can result

they are easy to check, just pop the top off the carbs (on the car ok) and there will be a little reservoir with a small pontoon that float in the gas and when its "full" pushes in a pin valve to stop the flow of more gas into the reservoir.

if they look cruddy id suggest a cap ful of "sea foam" (if you can get it in australia) into the gas (inside the carb) and let it sit overnight- that will dissolve most of the crud and when you start the car it will all get flushed out-
 

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I just cleaned my 36 IDFs and replaced the gaskets and needle valves. I was having the same problem with a poor idle. I found some dirt under the float bowls and I also found the needle valves were very worn.

This link was rather helpful:

http://www.carburetorclinic.com/tech_articles.htm

Here are copies of the manual pages which discuss the dual carbs.

Page 1
Page 2
Page 3

Anyone know if there is a Weber original rebuild kit for them? I've only been able to find an aftermarket one but I have been told that a 40IDF kit will work.
 

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I don't know if this is stating the obvious, but what kind of mechanic can't fix up and tune a set of twin carbs?
 

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I don't know if this is stating the obvious, but what kind of mechanic can't fix up and tune a set of twin carbs?
You would be surprised at the level of incompetence thats alive and well in workshops these days...there are mechanics and there are mechanics...ones with Engineering degrees are the ones to look for, they have the capacity to learn from experience...and ones between the ages of 40 to 70 usually have respect for what they are working on...
 

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Discussion Starter #9
Yes thats true, my mechanic is good for my old 1975 Ford ltd i have you know with the holley carb etc! He's never worked on an alfa and he knows how fussy i am! At least hes not the type to say he can do it and end up screwing it up!
He did recommend someone local to me who has alot of experience with webers so i might take it there.
 

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I met a mechanic who did'nt even know what a vacuum advance was! I got my car our of there so fast!
 

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Discussion Starter #11
I am currently looking for a new mechanic to work on my cars, i have had that many shonky ones over the years, it is so hard to trust someone to work on your car, for that reason i only get mobile ones out so i can watch them..........all i want is a decent mobile mechanic.........i dont think i will get the one who cant tune up the twin carbies back for any of my cars, he cant be any good if he cant do that, what do u reckon?
 

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Im not totally surprised that the guy you use doesnt know how to tune webers, a lot of people are afraid of them and Italian cars arent something a general mechanic would work on every day. I would suggest perhaps going to a good dedicated carburettor/injection workshop, then they will atleased know what webers are.
Im all in favour of "if you want something done right, then you have to do it yourself" or perhaps its worth contacting you local Alfa Club and they could put you in touch with a knowledgable person? If you were in Adelaide Id say swing by and I'll take care of it all for a slab of beer...:D
 
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