| January/February 1985

Upright exhaust and Zenith

Upright exhaust and Zenith K-5 carb, adapted from P30D power unit.

314 W. Wisconsin Greensburg, Kansas 67054

The McCormick-Deering 15-30 tractor, as originally built from 1921 to 1934, was a kerosene-powered steel-wheeled powerhouse which developed 15 drawbar and 30 brake horsepower, until refinements in 1929 increased the power output to 22 drawbar and 36 brake horsepower. This tractor was referred to throughout its production run as a 15-30 by IHC, as the name 15-30 had become famous with farmers across the nation. This was a tractor which, along with the famous John Deere 'D', made the transition from horsepower to horsepower complete. The 15-30 and the D were evenly matched, as the D's rated horsepower was 15-27. The D was a two-cylinder horizontal-engined machine, but the 15-30 was a four-cylinder vertical.

The late 15-30, or 22-36 style, was one of the workhorses of this country's farm production during World War II, as production of new farm machines came almost to a standstill while the factories were engaged in war production. Many farmers couldn't afford to trade for newer equipment during the depression, and couldn't get it during the war, so that old tractor had to make do. The 22-36 had an IHC-built kerosene model RW 1  inch carburetor, which had a water-injection attachment, to add water to the intake manifold when the engine began detonating on heavy loads on kerosene. These tractors burned kerosene fairly well, as long as the engine temperature was maintained close to the boiling point. Many farmers who owned these tractors when the depression hit had no choice but to continue to use them until times got better, so most of them looked for ways to improve on the machine, increase its power, and prolong its usefulness.

The first change to be made was the switch from kerosene to gasoline operation. Kerosene was cheaper fuel, but it didn't provide as much power as gasoline, and as stated earlier, the engine had to be run much hotter to burn it efficiently. The excess heat, and the side exhaust blowing fumes in your face when the wind was right, led many farmers to decide their had to be a better way. The P-300 power units were identical in design to the 22-36 engine, but were equipped with an upright exhaust, 'cold' gasoline manifold, and Zenith K5 carburetor. When farmers discovered that the parts would interchange, these manifolds and carbs sold like hotcakes. As the changeover was made, it was necessary to cut a hole in the upper hood sheet to accommodate the exhaust, and as the left hood would no longer fold, the side-sheets were removed and replaced by wires to the hood latches. This is why the sidesheets are so hard to find today.

The P-300 also had a variable-speed governor, as opposed to the 22-36's single-speed governor, and this change came quickly as it was discovered how much better the variable-speed governor would operate.

Serial number plate from a late 15-30, or 22-36 style tractor. Note that immediately before the tractor serial number are the words '15-30 TRACTOR NO.' IHC preserved the 15-30 model designation to continue the good reputation of the 15-30, a model that most farmers were already well acquainted with.