IH 404 Carburetor Problem?

Ok, I am lost on this one. I ain't got gasoline running through my veins so please bear with me. My 404 just doesn't want to start. I took off the carb and had a tractor dealer's shop rebuild it. Also I replaced spark plugs, wires, points & condenser, dust shield, rotor, cap.

It almost wants to run but not quite. When I hold my hand over the air intake and suction builds it will try to run until I let air by. If I pour gas down the air intake it will run sweet and move through power ranges, when my cup of gas runs out it will run on for two or three minutes.

I am adjusting the idle screw, while it runs on dribble gas, per the operator manual instructions in the hope I get lucky. My next planned work is to pull and clean the entire air intake assembly and add fresh oil in the cup to insure that is not the problem.

And I will drain a pint of fuel from the carb and time how long this takes as I have read about that here. Since I can pour in gas and it will run as it should could something be wrong with the rebuilt carb? As noted above I'm not a mechanic but should I pull th carb again and if so is there some literature available to review the steps to rebuild one? Easy literature with pics that someone with limited ability can follow?

How a carburetor works is a mystery to me but if I have to slug my way through it I would like to know. I also have a zenith carb in an old truck that needs rebuilding and maybe I could at least try to figure out the mystery of the carburetor with some help.

I don't have much hair left and the way I'm pulling it out now on this 404 I'll soon have none. This tractor ran very good last year but I just can't figure out why not now. Any help is appreciated, and apologies in advance for the stupid questions.

Since it runs fine when you pour fuel in the intake I would look at governor to throttle connections or if the butterfly in the carb for the throttle is opening. Also checking the fuel flow as you already talked about.

Well it turns out YouTube is your friend. Many videos about rebuilding carbs. Gives the basic background info so at least a starting point for me. If I have to I'll order a rebuild kit before taking this one apart. Then I can retrace the steps and have spare parts if needed.

Thanks, I hadn't thought about the governor, I'll do some research on that.

I would try blowing air back up the fuel line where it is hooked to your carb. sounds more like a fuel obstruction to me or possible venting problem.

I'm going to oversimplify some, but in vast generalizations there are only two fuel circuits in the carb.

- main jet, usual brass tube pointed right up the throat of the carb, supplies fuel in proportion to airflow thru the venturi. Airflow regulated by throttle blade.

- idle jet, complex set of cross-drilled passages that ends above the throttle blade.

The float keeps the carb bowl from overfilling.

As you have found, an old tin can with the correct sized hole punched into it, dripping fuel into the intake at the proper rate could more or less supplant the carb.

The test you mentioned to open the hex plug at the bottom of the carb bowl and allow fuel to run into a clean tin can or glass jar is a good one. You can recycle this fuel back into the tank. But it should prove out the wellness or fault of the gravity flow part of the fuel tank (tank, sediment filter screen, sediment bowl, shut-off valve, fuel line, carb strainer screen). I forget the numbers for volume, but if the stream is extremely dribbly or it stops at any point, there is a problem. It should be a smooth steady flow.

Is the main jet no. 45 in the diagram open? Maybe the dealer rebuilder didn?t set it to the initial
setting say 2 1/2 turns from completely shut, your manual should tell you. If that is not open she won?t run if the throttle
plate is open anywhere above the idle position.
404 parts break down

It definitely sounds like a fuel supply issue to me. Make sure you are getting good flow to the carburetor first and if that is good, then you might need to see if some trash has plugged the fuel inlet or there's an issue with the float valve.