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Discussion Starter · #1 ·
While attempting to adjust idle I noticed that my Weber carb is spurting a little fuel when I throttle up. It doesn't do this at idle though. I'll attach a photo to illustrate the area. The small "leaf" on this assembly draws in and produces the dribble when I goose the throttle. I've got two Opel GT manuals but of course neither has Weber info. What is this part? What is it's function? Why is it leaking?
 

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Detritus Maximus
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Why that would be the accelerator pump! Kinds makes sense, huh? Easy to replace if the diaphragm is torn (evidenced by fuel coming out of the 'slot' around the 'arm'). Or, if it's leaking along the edge where the gasket is, it could be the screws have loosened (don't try to tighten them alot, you will cause more leakage problems), or the gasket has given up (potentially solveable with a little (VERY little) gas impervious sealant.
 

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Discussion Starter · #3 ·
Would that also explain the idle speed seeming to change after stoping and then re-starting the motor?
 

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Detritus Maximus
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It could affect it. If the accelerator pump is leaking, then the fuel level in the bowl could drop while the car is shut off. If there are other problems, float level wrong, idle not set correctly (from trying to adjust it while the carb leaks), or even a bad upper carb gasket, then it would be hard to tell what exactly is causing the problems. I'd get a new pump diaphragm and upper gasket. Clean all the passages and wipe out the fuel bowl. Then start fresh.

Is the carb from a different car/previous owner installation or did you put it on? There's no telling what someone else could have done or even where they got the carb.
 

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Discussion Starter · #5 ·
--Is the carb from a different car/previous owner installation or did you put it on?--

Yea it was apparently installed by previous owner and it does have other issues like the choke not working. I've decided to rebuild it so let's keep this thread going 'cause I'm sure I'll encounter problems that I'll need assistance with. Thanks for your knowledge.
 

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Detritus Maximus
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I wouldn't call it 'knowledge', so much as 'experience'.:D
But you're welcome.

Do you have and electric or water choke? I've had both and much prefer the water choke in colder weather.

Things to watch out for:
fuel inlet on engine side of carb (can cause vapor lock. Wrap line in loose fitting heat shielding to protect from heat from heater hose and the very hot air coming up from the exhaust manifold),

get a fuel pressure regulator (helps maintain consistent flow of fuel into carb),

secure the ball/socket on the linkage (mine was missing the little wire bail clip and would pop off when I hit bumps)

find out the specifics off the carb you have (write down all the numbers and all sizes of jets, emulsion tubes, needle and seat, etc.). The current Haynes Weber book is pretty good (and cheap). There are many versions of the 32/36 DGV, not all of them are suitable for the Opel without changing jets and such. They will work, just not optimum.

if you have a second electrical connection (or only one if you have a water/manual choke) and it is where the idle jet is suppose to be (high up on passenger side of carb), it must be hooked up or replaced. It is an idle shut off solenoid. Without power it cuts off fuel flow (anti-dieseling). If it is not working right and you don't know what it is, it will drive you nuts trying to adjust the idle and you will wonder why it keeps dying when you try to drive it). Ask me how I know-:D (Mine was a junkyard carb off of a Mercedes. A TWM conversion, complete with TWM cast aluminum snorkel plenum. $15.00 thank you very much!)

Oh, and the biggest thing:
Put one of those see thru cleanable fuel filters right before the carb. They work great for eliminating/confirming crud as a cause of carb problems. If you have muck and debris coming from the tank (car sat a long time or tank is rusting) put a filter before the fuel pump. It will prevent the debris/muck from gettint into the pump where it acts like grinding compound and chews up the diaphragm.

If you already know any of this, then don't mind me. When people ask questions, I find it better to not assume they know anything. That way I don't forget some crucial/basic info that will nbe like an epiphany later (OHHH! So that's why.......).
 

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Relocating the Weber Fuel Inlet

opelbits said:
Things to watch out for:
fuel inlet on engine side of carb (can cause vapor lock. Wrap line in loose fitting heat shielding to protect from heat from heater hose and the very hot air coming up from the exhaust manifold),
While you have the carb top off, it is well worth the effort to drill out the outboard fuel inlet, tap it 1/8" npt and put a brass nipple in there. Then pull the old pressed-in inlet tube, tap that and install a brass plug. This will route the gas line away from the heat from the exhaust manifold.
 

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Detritus Maximus
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Darn it! Now see, you just gave me one more thing to do to my car! It makes too much sense not to do it. :D
 

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Discussion Starter · #9 ·
Yea, I read about the outboard fuel inlet and the problems it solves. I may be able to do that. If not I'll do the shrink over the fuel line trick. As to Opelbits question...it's a DGHV carb. I removed the carb this morning and noticed the little clip holding the ball socket. All good there. Where does the fuel pressure reg come into play? The idle screw is in place so I don't have to worry about the solenoid attack. What's the device that is connected to the water choke? It protrudes toward the back, has a screw covering what appears to be a small adjustment screw inside and a rod that could actuate the choke mech in addition to the spring mech of the water choke????
 

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Detritus Maximus
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Fuel pumps can vary in output pressure, both from differences in pump and engine rpm. If you use an electric pump (Facet low pressure type) you can get pulsations in the fuel and much higher pressure than you want. The pressure regulator maintains a constant pressure regardless of rpm or pump type. Might even help with vapor lock a little (not so sure on this).
I run a simple cheap regulator set at 2lbs. I know my electric pump can put out much more (5+).


If I remember right, that is some sort of adjusment screw for the choke thing. It is not something to be adjusted in normal setting. It is done at the factory or when rebuilding (never had to mess with them. Even the old Webers I've messed with the choke internals were right where they were suppose to be) or when someone doesn't know what it is and 'adjusts' it. With the choke cover off, you can measure all the movements and specs. It's been awhile since I was inside one of those, five years or so. You'll have to confirm this stuff in a book.

The insulation around the fuel line is an optional kind of thing. We get pretty hot around here in the summer and I've never had vapor lock in my Manta (7 years daily driver) or my current GT (1 1/2 years daily driver) no matter what the traffic. Even sitting in traffic. But I used to have [problems in my old GT (no insulation/regulator). I'm not saying it cures it, but I can't see how it wouldn't help. I've had it on carbs with fuel inlets on either side.
 

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Discussion Starter · #11 ·
After closer inspection I think your right about adjustment screw. It would set how far open the choke is when off. On this carb it's fully open so I guess that's about right. You'd think when the choke is off you'd want it completely open. Right!
 

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Detritus Maximus
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If I remember it right, there are two adjustments that are made inside the choke housing when reassembling the carb. These are limiters or tensioners for the spring or something (my life fades, the vision dims, all that remain are memories....and those are pretty well knackered...). These are not to be confused with the outside adjustments you use to set the choke up on a particular engine.
I've got both the old and new Haynes Weber books. Both are decent, but the new one has more info on tuning. It's cheap and available at Autozoned.
 

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Discussion Starter · #13 ·
I ordered Weber rebuild parts yesterday from Gil and he was kind enough to discribe the function of the above mentioned "pod". It's the choke cut off. There's a diaphram inside that is actuated by an internal vaccum tube. When you tromp the accelerator it pulls the diaphram connected to that rod which in turn trips the choke to open. I'm replacing that diaphram, the accelerator diaphram and the power pump. Might as well do it right while its disassembled.
 

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Discussion Starter · #14 ·
The Weber rebuild went well. The motor fired up nicely after re-installing. I'm still experiencing idle problems though. It's got to be fuel pressure. I'm going to try the above mentioned regulator and extra filter. If there's no improvement then I'll be getting a new fuel pump.
 

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Before touching the fuel pump ...
I suggest check your timing,sparks plug gap, point gap and condenser.
I just went thru the same ordeal and that fixed it!
(BTW,I was also thinking "fuel pump" ) :D

Good luck!
 

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Discussion Starter · #16 ·
Much better now with electric fuel pump, regulator and better filter. The carb was starved for fuel and with the stock mechanical fuel pump (with may have been about fail altogeather) idle speed was constantly changing. I'll think I'll take a nice drive tomorrow.:)
 
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