94 carb leak at accelerator pump shaft
 

Hi,
I just rebuilt my original 94 carb which leaked EVERYWHERE. Now, it leaks at the accelerator pump shaft. :mad: I set the float to 1 - 11/32. I'm also having trouble with weepage at the bowl drain plugs sometimes. The fiber washers wouldnt seal at all so I used viton o ring seals which totally sealed one plug, and 99% sealed the other.

First timer here with flatheads. How can I seal this thing up?

Secondarily, can I adapt a 2bbl, maybe a webber? I put one on a 54 chev 6 banger once and it worked really well. Not worried at all about originality, just want the car to run well and not leak.

Thanks

Re: 94 carb leak at accelerator pump shaft
 

Well, that doesn't make a lot of sense. There shouldn't be fuel getting anywhere near that pump rod shaft. The wet side of that arrangement is the pump cup "well" next to that. Even a bad top gasket, you wouldn't think, would cause fuel in the pump rod shaft.
I used "nylon" washers on the two float bowl access plugs. Think I got them from charlie price's vintage speed shop years ago.
The "regular" gaskets usually supplied in a carb kit for those two locations frequently weep. (Even my Edelbrock 94 leaked there, right out of the box and brand new)

You frequently see comments about folks getting rid of 94's in favor of the Stromberg unit. My 94 doesn't usually have issues, so I stuck with it.

Re: 94 carb leak at accelerator pump shaft
 

Maybe its the throttle shaft leaking. But, there is fuel also on the bottom of the accelerator pump shaft. Perhaps its shooting up there from a throttle shaft leak? I assumed it was dripping off the accel pump shaft down onto the carb base, throttle, etc. and surrounding areas.

Re: 94 carb leak at accelerator pump shaft
 

I have experienced the same issue at times with leaks around the accelerator pump shaft (and other places too) after doing a rebuild. One thought I had is if the pump plunger doesn't seal well inside the accelerator pump well, it can get past the plunger seal and proceed to slobber out wherever it can. Some of the kits have a leather seal and some have neoprene. If that's the case, the other unwanted result is that you won't get an adequate pump shot of fuel from the accel pump down the carb throat upon hard acceleration. I'm thinking if the carb body itself is worn where the accel pump shaft rides it can contribute to the leak also. You may have other issues with your particular carb, but this is one condition I have encountered.

Re: 94 carb leak at accelerator pump shaft
 

The plunger (blue) that came with my kit was way too small. Fortunately the old one was in good shape so I reused it.

Re: 94 carb leak at accelerator pump shaft
 

Send it to Charlie Schwendler in NY for a rebuild and be done with it.

Re: 94 carb leak at accelerator pump shaft
 

I just spent 2-3 hours over the course of a couple of weekends screwing around with the one I have, which has maybe 2000 total miles on it. The rumor is, they don't like to sit and I found that mostly true. This one sat while I had the engine out and being messed with by the builder.... so in three months I experienced different carb behavior than I had beforehand.

That pump well is an interesting design. Not sure why exactly Holley did that. (tapered bore) I ended up replacing the pump cup with a new one (synthetic, just like the one that Edelbrock put in there originally). Still had a weak pump shot. I cleaned passageways, scrutinized parts and concluded that that squirter nozzle (as supplied by Edelbrock) is a piece of junk. No amount of cleaning, even with a needle drill bit, made that thing squirt even remotely the same on both sides. I ended up borrowing an original 71 nozzle, which solved the issue.

Additionally, my opinion, is that that top carb body gasket may not do the trick as far as sealing. I didn't sand the mating surfaces of the casting, they looked to be pretty flat and pretty smooth on this particular carburetor. I did go with a slightly thicker top gasket.... although this bucks the opinion of many people, who say it will eventually leak, this one has been dry for a couple of years after I initially changed the one that was on it from Edelbrock...... which leaked in way under a year.

Going back to that pump cup deal, if fuel could get on the top side, I'm not sure if it would make it all the way up to where it could wet the pump rod shaft and dribble down that way.
I guess anything is possible though....

Re: 94 carb leak at accelerator pump shaft
 

Sorry for the delayed update - I herniated a back disc and haven't been messing with the car. Anyhow, I took it out today and confirmed that the leak is just coming from the throttle blade shaft after the car is shut down. it's not real bad, but my attached garage doesn't need gas fumes in it. I ended up purchasing another throttle body which was supposed to be NOS - it's not, it's actually "rebuilt." I also got from vintage speed, a reamer and .005 shaft. The .005 shaft slides right through the new throttle body with no resistance, but there really isn't any play. I'm not quite sure what to do at this point. I have the rest of the carb sealed up and tuned pretty well I think at this point. I don't feel the "new" TB with .005 shaft will solve the problem.

Re: 94 carb leak at accelerator pump shaft
 

When I did my last my Rochester 4G, it had worn throttle shafts. In that case, I was able to get brass bushings that were inserted in the base and were reamed to accept the shaft. Perhaps something like that is available if you insist on doing it yourself.

My optimum solution at this time however, is also "Send it to Charlie".

Re: 94 carb leak at accelerator pump shaft
 

I’ve rebushed throttle shafts before, when the value of the carb was so high that you had to do it that way. Made the shaft bushings, etc. Not something you’d want to do again, that’s for sure. The setup for the 30 seconds worth of machining on the body was about 2 hours.
Unless you’ve got all the equipment, bushing materials and experience, you may want to ship it out to get it done.

Re: 94 carb leak at accelerator pump shaft
 

I was able to source the proper sized bushing kit; all I had to do is cut them to length. A regular drill was all the was required for the throttle body, as the bushings are press-fit. A piloted hone was supplied with the bushing kit. I don't know if they have kits like this for 94's or not.

Re: 94 carb leak at accelerator pump shaft
 

Try that on an Autolite 4100. I can assure you it's not simple.

Re: 94 carb leak at accelerator pump shaft
 

What has this got to do with Autolite (?) carburetors? Just trying to suggest some alternative solutions. If it works, it works, if not, on to plan "C". (I think "C" stands for "Charlie".):)

Re: 94 carb leak at accelerator pump shaft
 

Drawing parallels is not your forte.
Have a nice day. Merry Christmas!

Re: 94 carb leak at accelerator pump shaft
 

Yup Thats what i do. He always finds something. The mounting flange isn't flat, the throtttle shaft is worn and leaking etc.
It's always something more then just a rebuild.

Re: 94 carb leak at accelerator pump shaft
 

Update: I sent my carb to Charlie in NY. She still leaks, but it's 95% better. I can live with the amount of seepage I see now.

Re: 94 carb leak at accelerator pump shaft
 

You shouldn't. Knowing Charlie as I do, he's even more eager to have it fixed than you are. Things happen during shipping.

Re: 94 carb leak at accelerator pump shaft
 

I agree things can happen during shipping, which is likely what happened. I think he did a great job with the carb! car runs so much better now. As bad as it leaked before, I'm grateful he took on my carb job as I don't have the know-how to do what he did. I didn't expect the 73 year old metal to seal perfectly. Long story short - I'm happy! Not too worried about the slight seepage.

Re: 94 carb leak at accelerator pump shaft
 

I don't think you get it. It is my understanding that Charlie would prefer to do a job over several times rather than having a reputation for anything but the highest quality work.

The man is a true craftsman.

Re: 94 carb leak at accelerator pump shaft
 

Have you checked what fuel pressure you have? Too much fuel pressure can cause those symptoms, especially having leaks immediately after shutdown.

Re: 94 carb leak at accelerator pump shaft
 

I just Spotted this post ,69a has it right Fuel pump pressure . It also can be the power valve or Float level to high?/ Leaking ,The shaft normally isint fuel tight ,