My Webers are gushing gas from the top! What's wrong?
 

I'm in the process of bringing a '67 911 back to life after about a decade of storage. I did my research on this board and followed the proper procedures (marvel mystery oil in cylinders, fuel system flush, replace fuel lines, boil fuel tank, etc.)

So I turn the key to the first position and hear the Bendix fuel pump working. But soon I see gasoline erupting from these brass fittings on top of the carburetors! This is a Weber 40IDS carburetor which has no choke function. Does this mean I need to rebuild these carbs or is this supposed to happen? It was happening on both banks of carbs. The carbs look pretty clean and don't have corrosion anywhere. Here's a pic of the gushing fittings.

http://forums.pelicanparts.com/uploa...1174258961.jpg

By the way, I did have the air cleaners buckets on it when I tried to start it. Any ideas where to start? Also, I need new gaskets to go in between the air cleaner buckets and the carbs. Couldn't find it on pelican, anyone have a part number?

Floats/needle valves...check 'em.

+2 on the needle valves/floats. They are stuck and fuel is just filling up and spilling over.

I would bet money that "stuff" will be laying on the bottom of the fuel bowls. A cleaning and rebuild are in order.

Just my .02 cents.

+3.

You need an 18 mm 6-point 3/8” drive socket to get the cover off the needle & seat (N&S). Most have the socket turned in a lathe to maximize the purchase on the very short brass hex. Do this while the carburetors are still in place. It takes hard pushing down to prevent the socket from “camming off” the hex. .It then takes a sharp “rap” on the wrench to break the cap loose.

While you still have fuel in the float chamber, check to see if the accelerator pumps work OK.

Next is to take the top off the carburetor. Don’t drop anything in the stacks. It is safe to wire the throttle arms so you can’t open the butterflies.

Use aerosol carb cleaner on the N&S. See if the floats are free to move up. You probably should remove the float pivot shaft and inspect the bottom of the float chamber.

Don’t mix up the tops side-to-side and keep each float associated with its original chamber.

It would be useful to use the aerosol to clean the idle passages.

If the accelerator pumps don’t work or the idle passages won’t become free, it is time to take the carburetors off for a through cleaning and new accelerator pump diaphragms. Get gasket/rebuild kits.

I forget, did you previously go through your distributor?

Best,
Grady

Just rebuild them, if they had run for 10 years they may be ok but sitting for 10 years means they need a kit. Just get a pair of kits and install them so you know its all good. My favorite for cleaning carburators is leaving them disassembled in a a bucket of simple green overnight. No need for the strong chemicals if you do that. Almost everything will be dissolved. An alternative that also works is to have them dipped somewhere that rebuilds carburators. Be careful as to how long you dip them though.

Before you rebuild them, find out why the fuel bowl is overflowing. Did fuel just come out of a single set of tubes or all? If all, look at the fuel pressure. If it's less than 4psi and/or fuel is leaking from just a single throat, look at the float inlet valve as the source. It's not shutting off the fuel.

Sherwood

Gently poke a small tool down the overflow tubes where the gas is coming out and see if the floats are floating. You may be able to free them this way if they are stuck, but you need to open up to see what is going on.

Thanks for the advice, all! Will report back what I find. I'll get this 911 running yet!

>I forget, did you previously go through your distributor?

Distributor? No, but you gave me good advice on my starter a couple days ago. I'll follow your steps above to get to the bottom of this.

>You need an 18 mm 6-point 3/8” drive socket to get the cover off the needle & seat (N&S).

Is this the cover you're talking about? http://forums.pelicanparts.com/uploa...1174847195.jpg

If so, its only a 16mm socket. I have a 6-point socket that fits it really well.