The Fordson Tractor Pages Forum

Hi, first off want to say their has not been a day of regret getting this old 58 New Major. Might have took alot of money to get running and might have a terrible wine in the rear end but i still love the tractor. My question is toward the throttle plate and possible cause of black smoke. When pulling a 5' bushhog which really isnt noticed by the tractor in even the tallest of trees, shrubs, and grass it is pretty constant to see a small amount of black smoke coming out, can get to be heavy black smoke at times when i really drag it down. I just wondered if it is normall for the throttle plate to have the stop screw set to where the plate only comes about half open at full throttle,and could this cause enough restriction to cause the black smoke. Most times i only run the tractor at about 3/4 throttle because i am unsure of the rpms the tractor is hitting wide open.Need to find a way to get a tach on the engine or pto so as to be sure but also wondered shouldnt it be just flat out governed to 1900 and shouldnt over rev unless the diaghram has a problem. Thanks for any help if you can make sence out of that posting.

Black smoke is not a bad sign unless it is excessive. If you keep the air cleaner clean and if she is timed right, don't worry. All diesels will smoke when working hard under load.

The governor does not work quite as you indicate. You set the revs at (say) 1500. The pump rack moves the delivery valves to get the engine to this point and the governor diaphragm is sensing the pressure either side of the throttle plate.

If you reach a hard spot in the field, the load pulls the engine revs down and the pressure on one side of the throttle plate and therefore the diaphragm changes.

This causes the rack to move and increase the fuel delivered into the cylinders, to try and bring the pressure on both sides of the throttle plate back in balance. This is when you get your burst of black smoke.

If the load is too great and she can't get the pressure back even, diesel will still be fed into the cylinders as the diaphragm continues to hold the rack in the increased fuel position. Then the black smoke will be constant.

When conditions change and the load becomes lighter, pressure equalises on both sides of the throttle plate and therefore the governor diaphragm. The rack is then allowed to return to a position where it delivers the correct amount of fuel and the black smoke reduces.

We are told that the best way to use a diesel engine for best fuel consumption and engine life is to switch it off and not allow it to idle, do not over rev it with a light load and always run it so it is working between its maximum horsepower and maximum torque. The best guide to this is the engine revs for 540 rpm on the PTO. If you drive her at this speed whenever you are using her (within reason) then she will last you two or three lifetimes.

If you move the throttle plate by the throttle lever, you change the pressure on one side or the other depending on whether you open or close it. This change is transmitted to the pump delivery valves by the rack and governor diaphram.

This is a very simplistic explanation and is meant to give you an idea. It is not a thesis on vacuum governor operation.

Thanks i knew black smoke was the norm but wasnt to sure of how much is normal. Have gotten to used to the newer tractors. The brief description of the gov. workings is helpfull as well. Guess i'll keep working her till she dies then rebuild her and do it again. Right now been doing alot of bushhoging. Have cleared about 18 acres. Have about 15 left. Just love running over those cedars that are higher than the exhaust. Best i figure this tractor may be around 40hp but i bet it has comparible torque to a 50-60hp tractor. Thanks again

It is interesting that you mention torque.

The Mk2 Major was 44 hp and had torque figures of 148 ft/lbs, The Power Major/early Super Major was 51 hp and had torque figures of 171 ft/lbs.

When the "X" series was introduced in 1965 the 4000 was 56 hp and had a torque of 143 ft/lbs, so it was more hp but was 28ft/lbs less torque than the Super and 5lbs/ft less than the Major 10 years before it.

The 5000 was 13 hp more than the Super Major but with only 170 lbs/ft torque which made it only 1 ft/lb more than the vacuum governed Super.

It makes you wonder what Ford was thinking when it introduced the square or over square engine. The IH 614 had 225 lbs/ft for a tractor of similar hp.

I would have loved to see a 5000 fitted with a 2701E 4 cylinder, British designed engine. This was the industrial version of an upgraded Super engine.

The 5000 was a great tractor from the clutch backwards but the engine let it down and we lost sales to MF. (It still hurts after 44 years)

Hi Brian,

I don't know about the rest of the world, but having worked with Ford motor company on the supplier side in Australia I can assure you that the person who signed off on the engine did not ever drive a tractor with that engine fitted to it. Well I suppose they could not sue their own engine plant, but they certainly tried to hold everybody else responsible when a project engineer mucked up. I suppose it is because of the transition from an essentially family business to a global corporation. No responsibility just make sure all the paper work is in order. It is a pity as the Fordson tractor is one of Henry Ford's greatest achievements.

Regards, Frank.