gasoline pumping out top of carb, what could cause?

Stuck needle valve causing fuel supply chamber to overfill?

-Fuel pressure could be too high

-Return line could be plugged

-Float is stuck or mis-adjusted or a piece of crud is jamming the needle seat.

The float is the most likely.

Dave

Thanks for replies.

I put some carb cleaner down into the bowl and now it doesn't seem to be coming out the overflow tube. however, when i try to start the car, it doesn't want to start, and when it finally catches it dies within a few seconds. While its running its throwing out tons of smoke. I'm assuming too rich, and i've checked and rechecked the vacuum lines. Any suggestions?

Thanks again

-J

That would usually mean the float needle is stuck open. Sometimes you can thump the carb with a chunk of 2x4 or a rubber mallet and loosen it off, other times the crud needs to be cleaned out of it.

Mike

Masospaghetti wrote in news:em9egi$cv4$1@news- int.gatech.edu:

The tube you refer to is the bowl vent, which allows air in and out as the fuel level rises and falls.

Your float is sunk or the fuel inlet valve is not seating properly.

Is the fuel return line installed and not blocked?

There could be a ton of gas in the manifold. Crank that sucker with the throttle open a bit. Feed it enough throttle to keep it running, and see if it clears out in 5-10 seconds.

You should at some point check for gas in the oil if the carb dumped gas into the manifold.

Dave

You could still be describing problems with the float needle. It sounds like it is just letting a little in and it just runs the float bowl dry. How's the gas pump and fuel filter?

Mike

Crap in the fuel will prevent ANY carburetor from working properly. Years ago I made the decision not to do carb overhauls as bench jobs for this very reason.

Unlikely

Irrelevant in this application.

And how does that happen?

The piece of crud is by far the most likely. There really is no way for a float to become "stuck" but the piece of crud will hold the needle slightly off the seat. Invariably when people blame the carburetor for chronic problems with the float "sticking" they need a good inline filter right at the fuel inlet due torusting fuel lines or whatever.

Don

I use a metal baking tray for just this purpose.

I agree mostly, but I have found that if a carb gets all varnished up inside that if it is used on a vehicle that is driven infrequently, it will work fine once the car is running but when all the gasoline evaporates out of the bowls and then you restart it, the float(s) may actually stick to the bottom of the bowl. I have had this happen both on a '69 Valiant (Holley 1bbl) and a '73 Chevy pickup (Rochester 2bbl.) In any case, though, disassembly and cleaning is the fix and adding an inline filter is never a bad idea.

Oddly enough, in both cases I ended up replacing the carb anyway. The Holley because the metering block literally disintegrated when I put it in the dip bucket, and the Rochester because it couldn't keep an accelerator pump in it for more than a year, no matter what. The Valiant is probably running to this day with the Carter that I put on it, and I know the pickup was running well for years with a junkyard Q-jet which lasted over a decade before being replaced with an Edelbrock.

nate

Float valve(s) stuck open.

Usually from letting a carb sit with fuel in it until the bowl(s) evaporate dry. The nasty additives in modern fuels make a pretty good approximation to super glue when they dry out, and the float sticks to the bottom of the bowl where it comes to rest as the fuel dries out.

But it can also happen on a "remanufactured" POS carb from the parts store due to shoddy assembly work. I'd say more than half of the "reman" carbs I've seen in recent years have some gross assembly error in them.