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Discussion Starter #1
Hello everybody.
I have a little question about weber carbs. A technician who helped me to replace a distributor for an electronic one found out that there is a strange hose going out from carbs but ending nowhere. My english is quite limited so I provide pictures:

This is the hose.......

I goes from the bottom of both carbs.....


the view between the carbs .....



and the type of Weber...



Can anybody tell me where that hose schoud go???
Thank you very much
Michal

my car: alfa romeo spider 1600 european model with carbs, 1987
 

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Tough to tell exactly what you're trying to show in the pix.
Does this mabe do anything for you?
(not even sure it applies to what carbs you have, but the funny Y shaped hoses on them are for balancing pressure across the 4 throats)
 

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Does the hose draw a vacuum when at idle??? Any idea what it's connected to on the bottom of the carb??

 

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Hi Michal,

I have a very similar car to you -83 euro spec 1600 with the same model webers.
Where does the hose attach underneath the carbs ? Is it at the front of the front carb? Mine has a hose from here to the breather tube on top of the cam cover . These pictures might help - but it is just on the top right corner . I can take some more if you need IMG_0047a.jpg

IMGP2144a.JPG
Hope that helps
David
 

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That may be the fuel drain hose from the airbox. I made mine longer so that it drains past the starter motor.

Rich
 

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OK - now the red lines make sense.
Definitely fuel drain hose . Smaller diameter tube on mine , unless Michel has very small fingers:)

To answer your original question , it does not connect to anything , just allows any fuel in the bottom of the airbox to drain away .
 

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Just a dumb follow-on question or two (mine don't have tubes): 1) why would there be fuel in the airbox enough so to drain, and 2) what is a safe place to route these; how long should the tube be? I believe there are two such connections one in front and one in back. I have a Euro Alfetta 01655 2L engine with Dellortos. Thanks, B

PS: I ask because I had a 16" dia puddle of fuel on the garage floor after starting it up and warming it up the other day. A float hanging up or crud under a needle valve?
 

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Get the occasional "spitting " back through the Webers, guess this can blow some fresh fuel outwards. The system is not designed for much - the holes in the base of the air box are tiny ( < 1mm ) . Maybe Dellorto's are better behaved than Webers?
The common drain tube routes down to just below the level of the cross member- far enough that any drips go on the floor - not the car .
16" puddle does not sound good :eek::eek: Assuming no cracked hoses , needle valve/ float assembly is probably first place to look.

David
 

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New hoses, triple checked clamps, not the fuel pump or filter (crimped gasket). Must be carbs.
 

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Gas expands quite a bit as it warms up. Cold fuel in the tank, drive the car a while, then park. Engine heat eventually soaks into the carbs and the fuel in the bowl expands, often overflowing a bit. I've had a bit of gas collecting in my intake air box for many decades....

Robert
 

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Hi Robert,

I can often smell gas on hot days when the car is stopped or moving slowly. I cannot find a leak. The plenum is always wet with gasoline. The float levels are correct and the fuel pressure is 3 psi. I used to get vapor lock on hot days and I fixed that by keeping the fuel line as short as possible. Do you think that pressure buildup in the gas tank could contributing to this.
 

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Does your car have a vapor recovery system? Common on US cars after mid 70's (plastic tank in the trunk). On these, the small tubing sometimes gets clogged and can cause a lot of gas odors.

If you don't have this, then the gas cap will be vented; this style has been around since the 60's. Some gas odors are just common for cars of this era. Be sure you have a properly installed and adjusted fuel pressure regulator. Webers don't like fuel pressure more than 3.5 to 4 psi and will flood if it's higher.

Robert
 
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