Fuel System: R-2 Carter AFB Carburetor Rebuild for 1963 R-2 Avanti

[HB63A2]

Greetings all. My R-2 Avanti has been running well until yesterday. While I hadn’t run it for almost a month due to the weather, snow, salt, etc. it started right up after cranking for about 5 seconds. Then I had to keep my foot on the gas or it would stall. I thought once it got to operating temperature it would smooth out, but after almost 15 minutes I let off the gas to check things out and it just stumbled and quit. When I got out I was surprised to see that it leaked a significant amount of gas! There was a pool of gas in the cavity on the top of the intake manifold between the back side of the carburetor and the vacuum tee pipe fitting. There was so much gas that it ran down to a cavity on the back side of the block under the distributor. There was also gas in the chrome valley tray under the carburetor. I took the bonnet off the top of the carburetor and the secondary butterflies were wet which might explain why it was running so ruff in addition to leaking gas. Since I could not watch exactly were the gas was leaking when the engine was running, based on the residue I could see, my guess is that most of it was coming from the Air Horn Gasket in-between the Air Horn Assembly and the bottom part of the carburetor. There was also a lot of residue where the accelerator pump plunger comes out of the top of the carburetor, but there was no pool of gas in the front area like there was on the back side.

I guess I’m looking at a total carburetor rebuild based on the fact that it is not only leaking gas like a sieve out of various areas but also running ruff. I’ve heard that carburetor is tricky to rebuild correctly so it is beyond anything I want to tackle as a novice. I live in Cincinnati, Ohio and was looking for someone experienced at rebuilding the Carter AFB Carburetor for a R-2 Avanti. I’d like to take the carburetor to someone in the area if possible, but if I have to ship it somewhere to get it rebuilt correctly so be it. I just want the job done right.

Thanks in advance for any help or suggestions on where to get this carburetor rebuilt.

HB63A2

[yeroldad]

Try using a handle end of a decent size screwdriver and rap on the top part of the carb while it's running. Often times the needle(s) and/or seat will have some crud on it/them and flood, like over and out of everywhere. Good to use some carb cleaner in the tank also. I use Lucas injector cleaner/treatment in the gas tank on a regular basis in all my vehicles.

[StudeRich]

It could be a stuck or sunk Secondary Float. At idle there should be No fuel action on the secondary half.

[mch]

Dave Thibeault does a fine job of rebuilding and has a quick turn around. 978-897-3158

Mark

[Gunslinger]

There's also Jon Myer of Myer's Studebaker in Duncan Falls, OH.

[JoeHall]

The AFB is one of the simplest carbs, and yours likely does not need a rebuild since it was working OK prior; they don't just self destruct over night, nor in a few months of sitting. Yours is more likely something simple, like a tiny piece of debris in the inlet valve, or an inlet valve that has a hardened rubber tip. With Shop Manual in hand, it is easy enough to take the top off of it for a look see. You can remove, the floats without any tools, and use carb cleaner to spray clean the inlet valves. If the valve tips are in question, you can carefully refurbish them with a piece of green scrubber pad, as used on the back of a dishwashing sponge.

Nothing ventured - nothing gained, and you'll have tremendous self satisfaction if you fix it yourself. You can find lotsa YouTube videos on AFBs, and how to tinker with them.

[Hawklover]

There's also Jon Myer of Myer's Studebaker in Duncan Falls, OH.

Plus a big 2222222 on Jon Myer, does not get any better than the accepted apostle of Studebaker;-)

[HB63A2]

Thanks all for your comments and suggestions! Sounds like the floats and/or inlet valves might be the likely problem. Nice to know if I can't get the AFB carb running right that there are a few people I can send it to! Sounds like some carb cleaner in the tank would also be a good idea.

HB63A2

[altair]

I don't think you require a rebuild, that much fuel leaking can only be the needle valve, (lucky there was no fire). I have had my AFB apart several times, disconnect the throttle linkage and all the small connecting rods, removing the Jesus clips is the only tricky part they can fly and never to be seen again so be careful with those. Once they are off remove the top screws, you will probably see the fuel at the top of the bowl. Suck the fuel out with a syringe then remove the float pin and the float and check it for fuel logged. Remove the needle and seat assembly and check for debris also check the rubber tip of the needle for any damage. Do not adjust the float. With the fuel line disconnected attach a rubber hose to it, now with the float reassembled pour some fuel in the bowl and blow gently into the tube, as your filling the bowl you should not be able to blow into the bowl if the needle valve is closed.

[JoeHall]

With the floats removed, I shake each to check for fuel inside; it's not uncommon in old carbs. The good news is Edelbrock clone floats and inlet valves easily swapped into my 1967 Buick AFB recently. For the inlet valves, I remove them and use a green Scotch pad to polish the (3) contact surfaces of each needle, then place the rubber tip of each needle into the Scotch pad and twirl back and forth while pressing lightly; this resurfaces the rubber surface, removing any grooves embedded over the decades, but be careful not to deform the rubber. Then I use the pad's corner, twisted to q'tip size, to push into each inlet valve recess and twirl, in order to polish the innards. Ditto for the float pins, each float's tang surface, at the spot where the metal needle backside rubs and scars it. This makes everything work like new. To test the inlet valve seals, I hold the carb upside down and blow into the fuel inlet nipple, there should be NO blow by. Also, while the power jet rods and pistons are out, I use the pad to polish those, including the pistons and bores. The AFB is about as simple a carb as was ever made. IMHO

[JoeHall]

For the leather accelerator pump plunger, I work Vaseline into the leather and roll the leather backward gently, all the way around, then roll it back into place and add more Vaseline, and use care in reinstalling it into the well.

[HB63A2]

Thanks all for the additional comments. I described my carburetor problem to a person that rebuilds carburetors and with the amount of fuel that spilled out (and evidence of seepage around the airhorn gasket and accelerator pump over time) he questioned if the fuel pump pressure was too high. The fuel pump had been replaced (with the correct one for a supercharged Avanti) just before I bought the car about four years ago. Since the car had been running alright (maybe a bit rich) up until the fuel spillage, I asked why the fuel pressure would increase. He said he had worked on other cars with problems similar to mine (fuel spillage and seepage as described) and tested the fuel pumps to find that they had excessive pressure (above 6 lbs.).

I just wanted to check and see if any of you have had such an excessive fuel pump pressure problem with your Carter AFB carbs with superchargers? I'd hate to tear down the carburetor if the real problem was the fuel pump. If the fuel pump pressure problem makes sense, any suggestions on a good fuel pump pressure tester and how to hook it up to do the test?

Thanks in advance for any help, guidance and suggestions you can provide.

HB63A2