Ferguson TO-30 engine revs to fast

I have a 1953 TO-30, SN 118700, with a Z129 engine and a Marvel-Schebler carb. Last fall I was discing a field when the engine suddenly went full throttle. I checked the external linkages but ended up diagnosing the problem as a bad governor. The governor was bad, the ball cage was almost gone. I just finished reassembling the tractor and the governor seems to be working properly but the engine still revs to full throttle. I reset all the linkages per the service manual and even disconnected the throttle linkage and ran it manually. I can hold the throttle linkage closed an get it to idle, but moving the linkage 1/16"-1/8" sends the engine to full throttle. I took the carb off and didnt see any obvious damage, but I assume this is a carb problem now. Any ideas of what to do next?

Is the butterfly valve loose?

When you say that you move the throttle linkage a small amount and it speeds up to high revs, are you just moving the vertical lever at the back of the Generator. Does the Governor make any attempt to shut down the engine. Check this by hand, push the vertical arm forwards and it should push back at your hand. As the revs increase, the Governor arm at the back of the generator should push towards the carburettor (and shut it down) if it doesn't do this then the Governor is not working. Are you sure that you the locating nib on the front plate of the Governor was located correctly. When the Hand Throttle Lever is in the closed position, the Carburettor should have the Throttle closed and be on the idle stop, when you open the throttle, the revs should increase and then automatically drop back to a speed corresponding to the position of the hand Throttle,if it does not move back, it is a governor problem. A small movement on the throttle linkage is normal, but the Governor when set correctly will balance this out. Have you checked the Springs, are they stretched or stuck with paint, there should be no gaps between the coils and the springs should not be rusty as that will make them weak. New springs are available, do not use any springs that you may have lying around and that look similar as they must be of the correct strength.
If you need more information about any of this, just email me, anytime..John(UK)[email protected]

I did pay particular attention to the tab on the new governor during reassembly, it also had an "up" arrow stamped into the new governor assembly front plate. With the throttle rod disconnected from the vertical arm of the governor lever, I manually worked the throttle rod and the vertical governor arm does push back toward the carb when the engine revs and moves back forward when I push the throttle full close. Both springs are clean and good, I had just replaced them with the proper springs 2-3 years ago. I can get the engine to idle with the throttle rod disconnected and held closed, from what I can see the throttle rod should have about a 1 inch stroke from closed to wide open but when I manually move the throttle 1/8" off of closed it races to full throttle, this is why I assume it is something with the carb. Could the carb have bad seals that are letting air in past the butterfly valve causing it to accelerate?

When I took off the carb, the throttle plate closed cleanly in the main bore and was not rattling around but I will have to recheck it to make certain the two screws are tight. It seems like there is too much air getting past the throttle plate as soon as the throttle plate is cracked open. Maybe air is coming in through the throttle plate pivot rod but it doesnt seem like it would be enough for it to go full throttle. Is there anywhere else air can get into the carb?

With no load on the engine it won't take much throttle movement to get the engine to rev up. I would go through all the external governor linkage adjustments again just to be sure. I know that if the throttle rod from the carb to the governor arm is adjusted to short it can rev way up, my MF50 was doing that when I bought it. You could try lengthening the throttle rod a bit (unscrew the clevis at the governor arm end) to see if that has any affect. Mark where the clevis is now so you can return it to its original position if needed.

Dan

Yes it could have bad seals, but that usually also increases the idling speed and you can't get a slow idle speed because it is sucking air at this point and making the mixture weak. But just check the spindle for the Throttle at the side of the Carb nearest the Engine, just try the Throttle spindle for movement up and down, there should be none,only a rotating movement, (this side gets the most wear because of the Governor load). If there is some wear, you can in some instances fit an "O" ring or a felt seal, that will also help to make it airtight, but you need to be aware that this could make the spindle harder to turn and it would influence the operation of the Governor. The stroke of 1" on the Governor Arm is about right and that should control the Carburettor over it's full speed range. If there is an air leak anywhere on the Manifold or Carb mounting, this too would cause an increase in idling speed and would not be the cause of what you are experiencing. Have you checked the fuel level in the Float chamber, I don't think it would cause your problem but it may do and is worth checking. The setting for the Float is 1/4"from the gasket on the top casting, to the top of the Float. Your description of how the Governor is operating would seem to be correct, but
I would do the Governor settings again, because while it is only moving 1/8" as you say, the Governor when set correctly would balance that out and control the speed properly. Is the Hand Throttle Lever just above the bolt on the top right corner of the Steering Housing to the Dash when fully closed, to alter this if necessary, slacken off the "U" clamp at the front of the Fuel Tank and move the Throttle Lever to the correct position. Now check that when the Lever is in this position that the Throttle on the Carburettor is fully closed, if it isn't,check that the vertical rod is JUST touching the Governor Arm at the bottom and that the Compensating Spring at the top is touching the Long throttle rod over the Engine. If the throttle is not closed at the Carburettor when you have done this, lengthen the throttle link from the Governor to the Carburettor slightly until it sits on the Idle stop screw. When you have this set correctly, check the maximum speed, if it is running too fast, slacken the "U" Clamp at the top in front of the Tank and adjust it slightly by turning the "U" Clamp so that the vertical rod is pushed down-wards SLIGHTLY until the speed is correct. Don't have it running too fast.
What you should watch for is when the Hand Throttle is closed and set at the correct position over the top of the bolt, is that the vertical rod should be JUST pushing the bottom end down on the Governor Arm, when you have this set, check that the Carburettor throttle is closed and sitting on the idle screw stop, if it isn't, lengthen the throttle link rod SLIGHTLY until it does.Make sure that there is no wear in the throttle rods at the pivot points or the pin through the Governor Arm or the Yoke end in the Throttle link to the Carb as this will cause some of the movement from the Governor to be lost and it can't control the speed properly.
If you need the information for overhauling the Carburettor, or have problems with the Governor settings, just email me direct and tell me what is happening...John(UK)[email protected]

You can fit the Throttle plate the wrong way around and it will not close completely, but if you do that the Engine will not be able to idle at all. If it will idle when you move the throttle rod by hand then it isn't the Throttle plate....John(UK)

Well it took me a couple weeks to get back to it, but I finally had time to put everyhing back together today. Im not sure exactly what the magic answer was but it works now.

I took the carb apart and replaced the throttle pivot shaft and exterior seal. I reset the float height, it was too close the the top casting. Then I reset all the throttle and governor linkages per Johns instructions. This took a couple tries but Johns instructions were more helpful than the manual. I think the top end is still running a little fast but I have to get a tach to check it for sure. At least I have a good starting point.

Thank you for your help, now I can put the tractor back to work just in time for our early spring.

If the Float was near the top casting (too high) it would cause over fueling.If you think that it is running too fast on top speed, avoid running it too fast until you get the Tacho and set the linkage. If you can't get a tacho let me know and I think that I have a manual way of doing that without using a tacho. Glad to hear that the instructions I sent worked for you, the manual can be difficult to follow I know, lots of ppl say that.John(UK)[email protected]