Autolite 2100 Carb on a Ford Mustang 289

I recently went through the carb on my '68 Mustang (289). When I went to start the car after reinstalling, fuel is spraying up and out. Any suggestions for my problem? I am planning to start with adjusting the float level, but not sure if that is the right adjustment to start with.

Did you put in a complete rebuild kit? What all did it include?

Yes, it included all gaskets, needle/seat/and gasket, power valve, pump inlet valve, diaphragm pump, and disc. check ball

Yes you have a fuel shut off problem with the float, needle valve, seat, or seat gasket. The fuel bowl is filling completely with fuel and venting liquid fuel. Check that the float is not sinking because it has picked up gasoline (IIRC that float is hollow brass). With the carburator assembled and drained of fuel, flip it over and you should hear the float free fall against the needle. Now blow into the fuel inlet. The float–needle should block air flow. If this test is okey return the carb to upright and invert it slowly from various orientations to make sure the float is not rubbing against the fuel bowl.

I had one case where a rebuild kit needle seat did not sit square in the inlet thread and had a slight leak at the seat gasket surface. The original seat still sealed so I used the old seat with the new needle. Worked just fine. I never figured out what the machining error was that caused the new needle seat to leak.

Float? Many kits don’t include a float. The float stops the flow of gas into the float bowl. The float could be bad. Check to see if it actually floats.

Great advice, thanks! I will check it when I get home. Thinking back, I feel like I may have errored when adjusting the float level, as well. Probably set about 1/4 inch too high.

While float level might cause this, I’d be surprised if it did. But I’ve been surprised before…

Just to be sure, you did not add an electric fuel pump did you?

Leave the carburetor attached to the engine. The top can be removed to access the float. In fact the engine will start and run with the top off but if you attempt that have a fully charged CO2 extenguisher handy. Of course you need that extenguisher handy regardless. Look closely at the needle to ensure it is properly located on the float tang by the keeper and the float pivot shaft is held in place by the spring clip.

And it is much easier to accurately set the float level with the bowl full of fuel. The float should be parralell with the top of the carburetor as it is suspended in the fuel.

If it’s not the float then I agree with what keith is getting at.

Before you attempt to start the engine pull the dip stick and while holding it away from yourself in a safe way run a struck match past the end of the stick. If the oil ignites it is severely diluted with gasoline and must be drained and replaced before operating the engine. One pint of gasoline will ruin a crankcase full of oil and operating the engine on diluted oil will do a great deal of damage.

Thanks Rod. It is not an electric fuel pump, so I don’t think that is the problem. You mentioned the spring clip. I think that may be the issue…is it the small clip that attaches to one end of the float hinge? My kit didn’t come with one and I didn’t see one when I removed the hinge. Also, I am unsure of how to place the retainer wire for the pin. What direction should the retainer wire sit - if up, I’ve got it all wrong and probably the entire source of my problem. (Looking at it now I picture this holding the pin and float in place) If down, does it lie on the left or right side of the needle assay? As you can tell, this is my first time tearing into a carb. I really appreciate all of your advice and help!!

The float pivots on a ~1" pin and the pin is trapped in its slots by a wire spring. Get the carburetor kit instructions and the exploded view should show the components in their relative positions. At the float tang a small wire hanger often suspends the needle to lift it out of its seat when the fuel level drops but some floats have a slots that trap the needle and lift it when the fuel level drops. The exploded view should show all possible configurations. I would suggest that you spread a large clean cloth around the carburetor to catch any pieces that might drop. And when assembled the needle and seat and float assembly should be recognizably functional in their operation.

And Re ethanol. It will be a problem until all rubber components in the fuel system are replaced with new ethanol stable pieces. The rubber hoses at the tank and fuel pump must be replaced sooner or later. Preferably sooner. There is a thimble shaped strainer below the needle/seat that will get plugged with trash and cause some difficult to diagnose problems if the old rubber hoses remain.

I’ve rebuilt a Motocraft version of basically the same carb. I think the others are right here, something’s preventing the inlet valve from turning the gas off to the carb when it is already full. Float or inlet parts probably. Once you get that solved, it is critical to engine performance that the fuel level be set precisely to spec for the engine, and that’s done with the float too, so now’s a good time to make sure that is correct as well as fixing the leaking fuel problem. My rebuild kit came with a sort of movable paper gauge to assist in this setting. I set it on the bench, not on the car.

I actually have a similar problem to yours, not with my car, but with my 2 cycle engine weed whacker. The fuel system was clogged up so I removed the carb and discovered all the gaskets were shot. So I replaced the gaskets and seals, thought I had it back together ok. But now when I fill the tank with gasoline and tip the whacker upright (gravity feed fuel system) the gasoline just leaks out the carb air intake in a big ugly squirt of liquid money. No good. Hopefully we’ll both get these problems fixed in short order. Best of luck.

fyi, some technical diagrams & info on the Autolite 2100 carb.

The fuel spraying “up and out” suggests to me that there’s a gasket and/or O-ring missing. A failure of the needle valve would simply allow the bowl to pressurize and spray into the venturi. I can’t envision it spraying “up and out”.

Had that problem with an autolite 4bbl,basically 2 2bbls,in my situation the power valve was flooding the engine with gas

Thanks again! I still feel like there is an issue with the hinge pin on the float. The schematics show a retainer spring on older versions, but it is not on the diagrams for '64 and up. It seems like there is enough play in the pin that it would allow the needle valve to let fuel in, whether the float is working properly or not. I still have not had time to try Researcher’s suggestions yet…hopefully this weekend.

maybe something has dissolved completely and that s why it wasn t in carb when it was disassembled