Last weekend, while waiting on some brake parts for my truck, I decided to replace a couple of gaskets in my two barrel carb that were seeping. I replaced the main body gasket, and the throttle body gasket. Reassembled everything, reinstalled it, but haven't tried starting it until today, when I completed my brake work (hopefully).

When I tried to start the truck today, it turned over, fired, then died. Fuel was leaking out of the carburetor, but it was hard to tell where from. It looked like the main body gasket. Now, when I crank the truck, nothing happens. I have a clear fuel filter just before the fuel inlet on the carb, and I can see that it's not full of fuel. However, when cranking, it doesn't seem like the mechanical fuel pump is trying to fill it, or the engine is trying to pull the fuel through.

I'm sure there's a simple answer to this issue, but I'm just not having any luck. Ideas?

 

The engine won't suck it up thru the carb, it just doesn't work that way. The pump has to push it to the carb. Pull the line off the carb and crank the engine, with the hose pointed into a narrow-necked 1-liter coke bottle (it won't splash back out from that). If you see fuel pulsing out of the hose, then there's a problem in the carb. Sounds like it could be that the float is stuck closed.

You aren't out of gas, are you???

 

The first thing I would do is pull the plugs and check if they are wet with fuel. If they are you most likley have trash in the needle and seat in the carb letting it flood. If they are dry check for spark and if all is well with the ingnition system put the plugs back in and spray some carb cleaner down the carb and se if it will fire on it if so you have a fuel delivery problem. I would keep a battery charger on it so you don't hurt the starter from low voltage and the ingition system has enough power to fire while cranking.

Hope this helps, Mike

 

Went out and poked at it a bit more, took the fuel line off and stuck it in a plastic bottle, fuel pump seems to be working okay. I guess I'm going to be pulling the carb off again tomorrow to sort out what might be wrong.

 

take the carb back down to the gaskets that you replaced. You might have installed a gasket that fits other types of carbs and has now blocked a fuel passege and wont allow fuel to be pumped forward....might be air-locked.
Just go back thru thre carb to insure the gaskets are correct, compare to the old ones where possible.
good luck with it, Ed

 

Took it apart again, the fuel bowl in the carb has fuel in it. All the gaskets match the old ones.

The truck will crank, fire, and die. No amount of playing with the choke, throttle, etc makes any difference. If you hold the throttle down and crank it, it'll fire, rev up, and die.

Any ideas?

 

Even though the gasket matches the old one , are you sure you have it on carb correctly maybe flipped over or something closing fuel flow . It sounds like something simple like that as it ran before new gaskets.

 

Starved for fuel for some reason. Maybe a chunk of something stuck in a passage from the disassembly or maybe there's an air leak between the carb and the intake.

 

Is this a Holley 94-style carb with power valve on the underside of the bowl? Check the throttle body-to-bowl gasket joint. Sometimes the power valve will prevent the two surfaces from seating (the dome hits the throttle body casting) and you get a big air leak. If the new gasket is thinner than the old, it could happen.

 

Well, it turns out that the throttle body to main body gasket is indeed leaking. It just took several cleaning and starting attempts to find it.

If it is because the new gasket is too thin (and I no longer have the old one), what do I need to do to ensure a replacement new gasket isn't too thin also?

 

Use two of them. Depends how much of a hurry you're in, but several carb specialists sell gaskets individually. Was there just junk preventing a seal? The power valve dome hitting the body is relatively rare, to be honest. Try fitting them together with no gasket. If it doesn't hit and you don't see any gaps, you're golden!

If it does hit, you can use two gaskets, or buy a proper power valve that is made specifically for 94's (not for modern Holleys). I forget who is making them, but they have no radius on the bottom of the threaded stem portion and are lower profile at the dome.

Also, you can use a thinner power valve gasket (so it seats deeper), some people use thin copper washers (well annealed). That may gain you some room, but it may also leak... Don't you love carburetors?!

 

I thought about using two, but I wasn't sure if I could. Ironically enough, the main body gasket and the throttle body gasket seeping were the reason I took it apart to begin with. When I put the throttle body on without a gasket, it seems to match up okay at the corners where the three screws hold them together, but I can see light through a few spots toward the center.

My original plan was to let this one leak, then replace it with a four barrel intake and carb at the Super Nationals. When I didn't make it to the show, I figured I could just stop this one from leaking. Simple, right? Oh well.

 

The saga continues. I replaced the throttle body to main body gasket, and the mounting gasket tonight. Exact same problem, only now it's leaking where the throttle rod (that the two plates mount on) goes through the throttle body. I don't have any parts in my rebuild kit that look like they would go there.

Is it possible to repair the new leak, or am I looking at a new carb by now? What would it take, aside from a new intake manifold, to drop a 4 barrel on it? That's my eventual plan anyway, and it's pretty frustrating to be chasing leaks on a carburetor I don't plan to keep more than a few more months.

The leak actually doesn't appear to be all that severe, possibly no worse than the original leak that I was trying to fix. Is it possible that there's something else going on, also?

Thanks!

 

Are you saying that the throttle shaft is sloppy in the throttle body casting? If so, they sell oversize shafts and reamers to correct that problem. Personal opinion, send it to someone who does this for a living, or buy a quality rebuilt carb. Speedway or Vintage Speed sells brand new throttle bodies with new shafts and butterflies already installed.

 

Yet another update. I called the parts store yesterday and they put an inquiry in to the main office. Long story short, they can't get a rebuilt carb for a '56.

However, we found a Holley 2300 for a '57 F-350 with a 272, and will have it tomorrow. I'm not sure exactly what carb I have, as it has no tags, no numbers, and simply the Ford logo cast on it. I see from pictures that it looks a bit different from a 94. Should I expect any problems with a 2300? I don't really forsee any issue, but I wanted to ask the experts.

Thanks!