Tractor Principles / The Action, Mechanism, Handling, Care, Maintenance and Repair of the Gas Engine Tractor

by Roger B. Whitman

If an attempt is made to shift the gears while they are in motion, the result will be that one will grind against the other, and there will be rapid wear and probable breakage. It is because gears cannot be shifted while they are moving that manufacturers instruct users not to attempt to shift on a hill without first blocking the wheels. The reason for this is that the brakes may not hold the tractor, and if the gears are pulled out of mesh, the machine may start to run down hill; as another speed cannot then be engaged because the gears are moving, there will be no control over the tractor.

Never coast down hill; always run with one of the speeds engaged. By switching off the ignition the motion of the tractor will drive the engine, and this provides the best possible brake. On low gear, the engine will turn in the neighborhood of eighty revolutions to one turn of the driving wheels, and the work required to do this will check the tractor on the steepest of practicable grades.

A tractor is not built for as accurate and delicate steering as an automobile and should always be slowed in making a turn; this is especially true when hauling plows or other loads in the field. It is difficult to control the tractor if a turn is made at high speed, and the machine is liable to tip over.

In steering and in engaging the clutch, the action should not be jerky and abrupt, but gradual and smooth. Letting in the clutch suddenly will start the tractor with a jerk that will strain it from end to end, and an abrupt swing of the steering wheel will have the same effect. Making these motions smoothly and steadily will cause the tractor to change its direction or pace with the least possible strain and effort. This, of course, increases the tractor’s life.

In much of the work done by the tractor, the varying conditions of field and soil make a continual change in the load, and the tractor must be handled accordingly. The change from an uphill to a downhill haul, and from sand or light loam to gumbo, will require the gears to be shifted in order that the engine may neither labor nor race in keeping the outfit at its work.

There should be no hesitation in coming down to low speed when the engine shows by its laboring that the effort of working on high gear is becoming too great. The engine cannot deliver its full power unless its speed is maintained, and low gear is provided for those times when the load is too great to be handled on high. Use high speed whenever it is possible, but trying to force the tractor to run on high with too great a load will lead to a breakdown.

High speed should be used for light work or for moving from place to place, but the engine should never be run at a greater number of revolutions than that specified by the manufacturers. It is very poor policy to run the tractor fast over rough roads, as the pounding will inevitably injure it.

Cold weather changes conditions in the handling and operation of a tractor; there is difficulty in starting, lubrication is likely to be faulty, and there is danger of breakage in engine, radiator, and air washer through freezing.

Difficulty in starting comes from the use of the usual medium grade of gasoline, which is satisfactory in mild weather, but will not vaporize at low temperatures. Cold gasoline will not vaporize in a cold engine; to form a mixture it is necessary to use high test gasoline, which will vaporize at low temperatures, or to warm the engine to a temperature at which medium grade gasoline will vaporize.

It is advisable to keep on hand a few gallons of high test gasoline to use in starting, or even a mixture of high test gasoline and ether, half-and-half, for extreme cold weather.