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Leaky Weber DCOE 40
Posted by: jazzworkerbee ()
Date: August 29, 2022 12:16PM

As I was bringing my car up to temperature today, I noticed a little puddle on the cooling shroud, under the vacuum secondary housing. At first I thought it might have been condensation, but it was gas. Not a lot, but a steady drip. I took no chances and shut everything down. The Carburetor is still on the car, so I don't know the source yet, but I thought I'd ask before I start taking things apart, again. I rebuilt a Weber 45 (not the one in question) about 3 years ago, so this stuff is far from fresh in my mind. All I can think of is that there may be too much fuel pressure or a Maybe a stuck float valve?

A little context, it's a Spanish Weber 40 DCOE that was modified for progressive by Ray Sedman. Precisely when, I don't know because I bought the carb used, with a note that said it was jetted for a stock, EM 145 block. My 65 Corsa, for now, has an early block, and it was a good deal, so I picked it up. I did not rebuild it because the gaskets looked good and the inside was very clean. I remember looking at the jets, but I don't recall what they are. My fuel is delivered via Facet pump at 3 psi, fed through a glass bowl filter and Mallory bypass regulator so I can utilize the return line back to the tank.

Other than a basic rebuild and my two possibilities, is there something that I missed and should also check for while I'm in there? If, at all possible, I'd like to avoid an engine fire! Part of getting my car ready for the road was repairing damage from a previous engine fire that was caused by a faulty mechanical fuel pump. Suggestions are greatly appreciated.

Daniel Atkinson
Tacoma, WA
65 Turbocharged Corsa

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Re: Leaky Weber DCOE 40
Posted by: vairmech ()
Date: August 29, 2022 04:44PM

The first thing you need to do is determine where the fuel is coming from. Witout that the answers can be that you have an oil leak! LOL

Ken Hand
Handy Car Care
248 613 8586

Vairmech@aol.com

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Re: Leaky Weber DCOE 40
Posted by: zarfnober ()
Date: August 29, 2022 05:41PM

Judging by your photo, I’d check the hose feeding fuel to the carb, it looks about 1/16” too big for the inlet.

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Re: Leaky Weber DCOE 40
Posted by: jazzworkerbee ()
Date: August 30, 2022 03:51PM

Well, it isn't the needle valve because it's free of corrosion and moves freely. Nor is it the float because it is solid and cannot take on fuel which could be a leak source. Does that leave the accelerator pump or a slightly out of place Venturi?

I started it up again and it took a few minutes for the dripping to start. The leak appears to originate just above the vacuum mechanism, but I'm waiting for it to cool down before I take it apart. For all I know, there's something common with this mod that I don't know about, yet... I'm guessing/hoping that it's something simple, but being new to this, I may not see it without some guidance from folks who have more experience with Weber DCOE carburetors with the progressive mod.

Daniel Atkinson
Tacoma, WA
65 Turbocharged Corsa

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Re: Leaky Weber DCOE 40
Posted by: jazzworkerbee ()
Date: August 31, 2022 12:20PM

I may have discovered something that strikes me a little odd. Someone soldered the secondary pump jet closed. There was fuel pooled in housing, unlike the primary that was both open and dry. between that and the old o-ring, that may have been the source of the leak, but I don't understand why someone would seal off a pump jet. Has anyone here come across that before? If so, is there an explanation as to why?

Daniel Atkinson
Tacoma, WA
65 Turbocharged Corsa

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Re: Leaky Weber DCOE 40
Posted by: jazzworkerbee ()
Date: August 31, 2022 01:24PM

Nevermind, I lucked up and caught Ray Sedman on the phone and he gave his usual thorough explanation followed by an atta boy and pat on the head. I forgot that he closes the secondary pump jet and enlarges the primary to feed both during short periods of boost. So, as far as this mod goes, it's normal to find the secondary pump jet closed.

Turns out, my mod is quite old and likely an original from Warren LeVeque, R.I.P. Mr. Sedman thinks that it may be a worn out gasket on the bottom or possibly that the bracket that holds the vacuum mechanism is flexing a bit. I'll try replacing it before I send it down to Northridge for a rebuild.

NO FIRES PLEASE!!!

Daniel Atkinson
Tacoma, WA
65 Turbocharged Corsa

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Re: Leaky Weber DCOE 40
Posted by: jazzworkerbee ()
Date: September 18, 2022 03:26PM

Well...

Pulled it apart, cleaned all of the jets and replaced the gasket on the bottom. Somehow it leaks more than before and spewed fuel through the vacuum line and out of the vacuum diaphragm as well as the secondary air horn. I have no idea what's happening now. Any ideas?

Daniel Atkinson
Tacoma, WA
65 Turbocharged Corsa

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Re: Leaky Weber DCOE 40
Posted by: 63turbo ()
Date: September 18, 2022 04:55PM

Any screws or bolts that maybe you forgot to tighten back down? the opening and closing of the secondary is from vacuum, and that vacuum line is on the venturi on the primary- its possible for fuel to get in that line just from use. If you have fuel leaking from that spot, it is either because the fitting is loose or the tube attached to that fitting isnt on tight enough. A long time ago, I made it standard practice to put a zip tie on all flex lines that were normally attached with a hose barb (like that vacuum line) because of minor leaks I had seen previously. Try zip tying both ends of that hose, and verifying that both the fitting on the primary and the venturi lock bolt on the secondary are tight. Those things dont have gaskets on them, and need to be tight to prevent fuel from leaking through the threads.

------------------------------------

Kevin Nash
Friday Harbor Washington
63 Spyder, Daily driver, EFI read about my project here: [corvaircenter.com]
first test start on EFI here:[www.youtube.com]
first official EFI boost test here:[www.youtube.com]
My new fan! [corvaircenter.com]
engine less 62 Spyder
Canadian 64 Monza Parts car
Test Start#2 [www.youtube.com]



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Re: Leaky Weber DCOE 40
Posted by: 63turbo ()
Date: September 18, 2022 05:13PM

Heres a picture of mine when it was carbed, showing the zip tie technique

------------------------------------

Kevin Nash
Friday Harbor Washington
63 Spyder, Daily driver, EFI read about my project here: [corvaircenter.com]
first test start on EFI here:[www.youtube.com]
first official EFI boost test here:[www.youtube.com]
My new fan! [corvaircenter.com]
engine less 62 Spyder
Canadian 64 Monza Parts car
Test Start#2 [www.youtube.com]



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Re: Leaky Weber DCOE 40
Posted by: jazzworkerbee ()
Date: September 19, 2022 10:45AM

Thank you Mr. Nash! I have some small 4" ties, but they don't cinch very tight. I used weed-eater fuel line which was a smaller diameter than the nipple, so it was pretty difficult to attach. I thought it should have been tight enough--maybe not. Has anyone ever used pipe putty or nylon tape on the nipples where thy attach to the body to prevent leakage? I thought they were tight, but I'll double check again when it's in front of me again.

I checked inside again and all of the jets are clean, flow freely and all screws are tight.

Cleaned all of the fuel off the secondary bladder and tightened it back down. Heading to the hardware store to see if I can find a smaller tie, some extra o-rings for the brass screws on the outside and find a stubby 9/16 to make attachment and removal a LOT easier for the nut on the firewall side of the manifold.

I'll try again later and see how it does. At least the replacement gasket didn't leak, but it's odd that it leaked even more than the previous time!

Daniel Atkinson
Tacoma, WA
65 Turbocharged Corsa

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Re: Leaky Weber DCOE 40
Posted by: jazzworkerbee ()
Date: September 19, 2022 01:36PM

Well, I destroyed the fitting that lives under the venturi while trying to tighten it down and went all over town to find a replacement with no success. Can anyone direct me to an online source? The part is unique and Ray Sedman is a little difficult to get on the phone.

Daniel Atkinson
Tacoma, WA
65 Turbocharged Corsa

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Re: Leaky Weber DCOE 40
Posted by: jazzworkerbee ()
Date: September 20, 2022 12:26PM

Turns out that it's a combination of parts--a 7mm x 1 screw that was tapped to fit a nipple that screwed into it. Michael Leveque only had the nipples and not the entire assembly, so I'm going to try to back the broken part of the nipple out so I can reuse the screw. However, couldn't I just use a 7mm brake bleeder screw and just grind the bottom end off to allow vacuum pressure access to the diaphragm?

Daniel Atkinson
Tacoma, WA
65 Turbocharged Corsa

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Re: Leaky Weber DCOE 40
Posted by: jazzworkerbee ()
Date: September 22, 2022 01:27PM

I think I found the problem! My float was low and wasn't stopping the flow of fuel to the bowl when it was full. I set it a long time ago, so it's a puzzler as to how both the height and travel were so far off. Glad I remembered that the diameter of the stock, Gabriel front shock shaft is 12.5mm to serve as a reference point. Either way, it ran fine on one barrel after I plugged the vacuum port for the secondary and there were no leaks!

Thinking the vacuum nipple was a fitting rather than a custom, super delicate assembly made from a stock grub screw that was drilled and tapped to accept the nipple, I destroyed it when I tried to tighten it, thinking it was the source of the leak. I started to fashion a new nipple/grub screw out of a 7mm brake bleeder with a tiny brass tube soldered in and ground down at the end to form a grub point, but Ray Sedman has offered to save me from myself and I gladly accepted. I think my idea would have worked, but I'm perfectly happy to bow out and wait.

Daniel Atkinson
Tacoma, WA
65 Turbocharged Corsa

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Re: Leaky Weber DCOE 40
Posted by: jazzworkerbee ()
Date: September 26, 2022 12:13PM

Pegasus sent the wrong parts to Sedman, so there a bit of a delay. As such, I decided to try my brake bleeder theory and it seems to have worked out pretty well! the OD of the brass tube is a bit small, but it was left over from another project and I soldered a little nipple on the end. It fits as well as the other one and seems to seal up well.

Daniel Atkinson
Tacoma, WA
65 Turbocharged Corsa

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