1954 ford 9n jubilee tractor

i know this is not a car but here is my problem. my issue is . it runs and runs good. only if it is about 3/4 choked i have rebuilt the carb, new intake manifold gasket cleaned all fuel system. i have adjusted carb. and it still acts like it is sucking air. if i let it run unchoked it will die. i cant get it to idle low like it should. it is still a 6 volt system. but am converting it to a 12volt system. does anyone have any ideas? i have checked for intake leaks.already.

If you have to choke the carb in order to keep the engine running it means the engine isn’t getting enough gas. Air is free. But there’s got be enough gas for that air.


Fuel pump and filter?

Are you certain that the float is set correctly including the float drop?

yes i am certain the float is correct, and there is enough fuel to air.

If the engine stalls when it’s unchoked it means too much air is leaning out the fuel mixture. There’s a fuel delivery problem.


If the float is set correctly, the idle jet is out at least one turn and there are no vacuum leaks the main jet may be plugged. How was the carburetor cleaned when it was overhauled?

Biggest mistake I made is to sell the 9N in '83.
Are using 92octane-no ethanol?

Remember the 9N is + ground on your change over.

If I remember correctly (IIRC) those older 9N Ford tractors have a gravity feed fuel delivery system. There is no fuel pump. You can check it for good delivery by simply unscrewing the line from the carb. It should run out of the tube as fast as the diameter will allow.

Did you soak the carburetor body in carb solvent and blow it out with compressed air after the solvent bath?
If not, an idle passage could be plugged up and if so it will never idle or adjust out correctly.

Again, and on the if not theory, you might try removing the idle mixture screw, spraying some aerosol carb cleaner into the hole, and then appying compressed air to the hole. Sometimes this can remove any restriction; knock on wood.

Think there is a drain cock at the bowl.

There isn’t much to go wrong on the carburetor. They don’t get any more basic.

It is easier to ignite a richer mixture than a leaner mixture. If the spark is not good, you may have problems in the ignition system. I ran into this problem one time on my father-in-law’s Ford tractor. The tractor had a similar problem to your tractor. He thought he had fuel system problems. I filed and regapped the ignition points and that took care of the problem. Check your points, plug wires and coil. I may be way off base here, but you’ve gone through the fuel system, so take a quick look at the ignition system.

+1 @Triedaq - someone once said here ‘if you think you have a carb problem, check the ignition’.

@texases–I was taught that “Carburetor” is a French word that means “leave it alone”. Years ago, I overhauled a 2 stroke Lawnboy mower. I broke the glaze on the cylinder wall, put in new piston rings, put in a new needle and seat in the carburetor and replaced the points and condenser. When I pulled the starter, nothing happened. I checked for spark and it was a nice fat blue. I poured a little gasoline into the cylinder and it ran for about three seconds. I tackled the carburetor again. I reinstalled the carburetor and still no luck. I turned off the gasoline shutoff, pulled the fuel line off the carburetor and turned the shutoff on. No gasoline came out of the fuel line. It then struck me–I drained the gasoline tank before I started working on the mower. Filling the gas tank solved the problem. It did reinforce what an old mechanic taught me–look for the simple things first.

the ignition system is all new also. points condensor cap rotor plugs wires. everything. i have good spark. i checked all the wiring. still no go it has excellent fuel through carb. i checked that how the factory book says to check. i think i will switch it all over to 12 volt before i try to figure out what is going on here. my uncle said he had a problem with his tractor which is the same model and year. he switched his to 12 volt and never had an issue since. thank you for the comments and suggestions i appreciate it!!!

Good. How did you set the points and timing?

“Filling the gas tank solved the problem. It did reinforce what an old mechanic taught me–look for the simple things first.”

Yeah I did that with a snow blower once. Over-hauled the carb twice until I discovered I needed to turn the fuel on.

"i think i will switch it all over to 12 volt before i try to figure out what is going on here."
I don’t see how switching over to 12 volts will solve the problem unless the problem is the coil. If going to 12 volts solves your problem you had an ignition system problem. The only place where converting to 12 volts would make sense is that you might have faster cranking and quicker starting in cold weather.
One last thought–is your coil polarity correct? If the wires are reversed at the coil, the spark may appear strong, but actually be jumping from the outer electrode to the center electrode as opposed to jumping from the center electrode to the outer electrode.