Throttle

[Williamb]

I recently removed the tank , rewired the engine and fixed the hydraulic pump on my 1953 cub. Now when I start it the throttle doesn't have any effect and the engine runs at high speed only with the choke on. The throttle arm does move somewhat at the governor but has no effect. My general rule is when one thing gets fixed something else breaks. I have a new carb and replaced the fuel line. When I look at the governor from the left side of the tractor I see a spring attached to the governor but it doesn't appear to have any tension on it. YouTube has failed me so I hope someone here has some idea of the problem.

Thanks
Bill Buffat

[Glen]

Hi,
You didn't say, I guess you are talking about an IH carburetor, Zenith was used also.
People have said on here some of the low priced foreign made replacement carburetors don't work right.
The float level is wrong on some of them, and needs setting to the spec in the Cub service manual.

You could try cleaning inside the old carb, and use it to see if it runs right.
If you take them apart, pull the 2 halves straight apart for 4", don't twist them. There is a small idle tube attached to the top half, that sticks down into the bottom half. They have to be pulled straight apart to avoid breaking the tube.
Use carb cleaner, or solvent to soak the carb some, and blow out all the passages with air. Dirt can settle in the bottom passages, or anywhere also. Wear your safety glasses when using the air.

Below is a pic of the governor and spring from TM Tractor. That is how it should look.
If the throttle lever won't move it's full range, work oil into the pivot where the cotter key is, they sometimes get tight there from no oil. It takes time to work the oil through the pivot. The pin is solid in the governor housing, the arm turns on the pin.

[Waif]

There is a choke lever on the backside of the carb..If out of position ,you can be choking the engine when choke rod at operator station says choke is off.
Looking at the rectangular piece on the outside of the carb (the one you use your fingers on if handcranking) will tell you what position the choke plate is in , wherever you have the choke rod at...

When changing a carb . you need to adjust the linkage to governor at (attached to front of) carb.. Then as per service instructions (if they apply to your tractor) ramp the throttle up and down after adjusting carb air screw until it is a smooth transition between low and high..

[Williamb]

Sorry I should have been clear. The tractor ran fine before I fixed the hydraulic pump. The image shows the spring I referred to. I don't have the Zenith carb but the IH. The old carb had been jury rigged and I just couldn't deal with the float sticking anymore. It is difficult to operate the throttle so next lubricate the throttle pin.

Thanks

[Eugene]

Check to see if the choke lever and rod from the governor arm to the carburetor are in the right hole/arm on the carburetor.

Guessing, you have them mixed up.

[Bob McCarty]

A majority of the Chinese carbs I've opened have needed the float adjusted. Sounds like you're not getting adequate gas flow. Reread Glen's comments about splitting the carb. Save the old carb, they can be rebuilt.

[Eugene]

Now when I start it the throttle doesn't have any effect and the engine runs at high speed only with the choke on. The throttle arm does move somewhat at the governor but has no effect.

Check to see if the choke lever and rod from the governor arm to the carburetor are in the right hole/arm on the carburetor.

Guessing, you have them mixed up.

Edit. Easy check. Pull the choke rod and see if the choke lever on the side of the carburetor moves.