1950 cub leans out

[Greenthumbfarms]

Finally got a chance to work on the 1950 Cub that I brought to the bash in June. Still have issues with it stalling if throttled up when cold or throttled up too fast. At the bash, Gary Dotson rebuilt the carburetor, and seemed to think it needs a bigger jet. Would that be something good to try changing, or is there something else I should check first?? I'd like to get this one running a little better this winter.

[Bob McCarty]

The early carbs had either a .032 or .034 main jet. Aftermarket jets can be as small as .030. If you have any wire gauges, measure the orifice and see what you have. You may also need to change the discharge tube to match the jet size. I'm assuming you adjusted the carb to governor linkage after you reinstalled the rebuilt carb.

[Gary Dotson]

Well, that’s been a few months and the memory is fuzzy so I don’t recall how that all played out. If you have a set of number drills, you can use them as gauge wires to see what you have. Then, you can call Morgan, at McDonald Carb. to see what he has available. There’s no harm in trying a larger one, if one is available.

[Greenthumbfarms]

I will have a go with the drill bits to see what size the current jet opening is. I do believe I have a 0.030 and a 0.034 jet in my parts box, so I will compare to that. Is the discharge tube the same as the idle tube?
Bob, I believe we did adjust the governor linkage, but it wouldn't hurt for me to check.

[Bob McCarty]

. Is the discharge tube the same as the idle tube?

No, the discharge tube threads into the carb bottom and has a hex near the bottom. The idle tube threads into the carb top and is just a straight brass tube.

[Greenthumbfarms]

Well I got back to working on it today. I had picked up one of TM tractors replacement IH carburetors to use on another machine, and tried it on the 50 by chance. Runs smooth, and throttles up nicely, no issues with leaning out. Must have had something internal wrong on the original carb.
Now to find a better throttle "notched plate" or whatever that peice next to the steering wheel Is called. This one is worn put and the throttle handle jumps back.

[Bill Hudson]

Now to find a better throttle "notched plate" or whatever that peice next to the steering wheel Is called. This one is worn put and the throttle handle jumps back.

It is called throttle quadrant and here is a How To that describes how to rebuild one like you have. http://www.farmallcub.com/phpBB2/viewtopic.php?f=147&t=28536&hilit=throttle

Bill

[Glen]

Hi,
The notches on the throttle sector can wear over time, then the throttle lever can slip to the rear.
Sometimes the notches can be improved by filing them with a small 3 cornered file, that fits the shape of the notches.
They should be the shape of the 1 or 2 notches at each end of the sector that may be unused, if the lever doesn't move into them.

TM Tractor has a new throttle sector, if you would rather have a new one, or don't weld.
Below is their listing. It is a Case IH part, it says.

http://www.tmtractor.com/new/gv/689fp.htm

They have a listing for the lever, but it says they are out of them.

The place on the lever that touches the notches on the sector gets worn too, and may need repair.

Below is the listing, the 2 bottom pics show the shape of the lever where it touches on the sector.

http://www.tmtractor.com/new/gv/415fp.htm

[tst]

the aftermarket sector is a piece of junk, the notches are cut wrong so the lever does not stay locked in, IH wants like $150 for the factory one now

[Waif]

Well I got back to working on it today. I had picked up one of TM tractors replacement IH carburetors to use on another machine, and tried it on the 50 by chance. Runs smooth, and throttles up nicely, no issues with leaning out. Must have had something internal wrong on the original carb.
Now to find a better throttle "notched plate" or whatever that piece next to the steering wheel Is called. This one is worn put and the throttle handle jumps back.

As Glen mentioned , teeth wear. ( The quadrants teeth do too!)
If recalled right there is spring tension holding lever against it. Might check tension.

A few teeth seem to be found worn for me and file dressing improved the catch of the most worn tractors quadrant. Seems than on the sloppiest one I tightened the spring a little with/by it's through bolt. (?)

[Greenthumbfarms]

I might pick up a pre-made one for the sake of time, I'm not nearly a good enough metal man to expect the first one to come out right but I will have to give it a shot to have one on hand.
I recall Tim Talleur telling me the teeth needed to be rounded, it this true?

[Dale Finch]

Just slightly rounded so you can "slide" the lever fore and aft...but you should be lightly pushing the lever away from the quadrant, to minimize wear.

[Greenthumbfarms]

the aftermarket sector is a piece of junk, the notches are cut wrong so the lever does not stay locked in, IH wants like $150 for the factory one now

Are any of the replacement ones good? Repairing this one will be a summer project, and I would like to use the tractor to push snow I knight just tighten the spring tension on the lever to hold it in until I can rebuild the quadrant.

[tst]

I have only seen one repro, think they all came from steiner

[Dale Finch]

If you Google Farmall Cub Throttle Quadrant, they are offered by Steiner's, Yesterdays Tractors, Amazon & Ebay...could all be made by the same company??