Farmall F-20 Tractor Guide: Years, Horsepower, Serial Numbers, Value and Parts

The Farmall F-20 was International Harvester's bread-and-butter row-crop tractor of the 1930s. If you just bought one, inherited one, or are trying to get Grandpa's running again, this page covers what most owners want to know first: what year it is, how much power it makes, how many were built, what it's worth, and which parts wear out.

Rice Equipment opened in Clarion, Pennsylvania in 1937, while F-20s were still coming off the line. Today we sell new old stock parts for them. Shop all Farmall F-20 parts.

Farmall F-20 quick facts

Years built 1932 to 1939
Built by International Harvester, Rock Island, Illinois
Number built About 148,000 (serials FA-501 to FA-148810)
Engine IH 4-cylinder, 220.9 cu in, 3.75 x 5 in bore and stroke, 1,200 rpm
Fuel Distillate or kerosene, started on gasoline
Horsepower About 28 belt hp and 20 drawbar hp (Nebraska Test 276, 1936)
Transmission 4-speed
Weight About 4,400 to 4,500 lb
PTO 540 rpm
Price new About $1,000 (1936)
Came before / after Replaced the Farmall Regular. Replaced by the Farmall H in 1939.

Where the F-20 fits in the Farmall line

The F-20 took over from the original Farmall, the one collectors call the Regular (1924 to 1932). It kept the same basic idea, a tall row-crop tractor with a narrow front, but added more power and a fourth gear. The bigger F-30 came out first, in 1931, and the smaller F-12 came along soon after. In 1939 the styled Farmall H replaced the F-20.

Because the F-20 grew out of the Regular, a number of parts are shared between the two, and some F-20 parts also fit the F-30 or the McCormick-Deering 10-20. Each product page lists the models we know a part fits.

How many Farmall F-20s were made?

About 148,000. F-20 serial numbers run from FA-501 in 1932 to FA-148810 in 1939, plus a few hundred early tractors with a TA prefix (see below). One reference lists a total of 154,398, so you will see both numbers quoted. Either way, that is a lot of tractors, which is why so many are still around.

Farmall F-20 serial numbers by year

Find your serial number, then match it to the first serial of each year:

Year First serial number
1932 FA-501
1934 FA-3001
1935 FA-9760
1936 FA-41123
1937 FA-72982
1938 FA-112201
1939 FA-136042

The serial lists show no separate starting number for 1933. Some early-1934 F-20s carry a TA prefix (starting at TA-135000). Those were built with the Regular rear end. If yours has a TA number, tell us when you order.

Can't find the number? Our fitment guide covers where to look and what to send us.

Farmall F-20 horsepower

The University of Nebraska tested the F-20 more than once. Two of the tests show the spread:

Nebraska test Date Belt hp Drawbar hp Max pull
Test 221 April 1934 23.11 15.39 2,334 lb
Test 276 November 1936 27.84 20.66 2,927 lb

So the short answer is about 23 to 28 belt horsepower and 15 to 20 drawbar horsepower, depending on the year and setup. It was sold as a two-plow tractor.

Gray or red?

Early F-20s were painted gray. IH switched to the familiar red on November 1, 1936, the start of the 1937 model year. If you are restoring one, the build date tells you which color is correct.

What wears out on a Farmall F-20

These tractors are 85 to 90 years old, so almost anything can need attention. These are the areas owners and restorers bring up most:

Ignition

Hard starting and rough running often trace back to the magneto: dirty points or timing that is off. Old plug wires are another common cause.

Carburetor and fuel

A carburetor that sat for years usually needs cleaning and new wear parts, and the fuel strainer and its gaskets are worth checking at the same time.

Engine

Once a head comes off, most people do gaskets, valves and rings in one go.

Steering, cooling and clutch

Leaking steering gear seals are a common complaint on old Farmalls. Radiator gaskets and fan belts are cheap insurance before a long day of work or a show.

What is a Farmall F-20 worth?

A project F-20 doesn't cost much. Recent public auction results:

  • $625 (December 2022, Georgia): older repaint, engine stuck, wheels cut off
  • $850 (August 2019, Minnesota): on steel wheels, needed fresh gas and cleanup
  • $1,600 plus buyer's premium (August 2024, antique tractor auction): condition not listed

Running, complete tractors and good restorations bring more. For a current number, look at recent sold results on AuctionTime or BigIron for tractors in similar shape.

Farmall F-20 manuals, parts books and diagrams

If you're working on one, the IH books are the best reference you can have. The parts book is where you find the IH part numbers, the same numbers we list on our product pages, so it is the place to start if you are looking for a parts list or parts diagram.

With the IH part number in hand, you can match a part exactly. Send us the number and we'll tell you if we have it.

Need a part for your F-20?

We stock new old stock Farmall F-20 parts: original IH parts that were never installed. Start with the Farmall F-20 parts collection, or call (814) 226-9200 (evenings Eastern are best) with your serial number and the part you need.

Sources: TractorData.com (specifications, serial numbers, Nebraska test results), the University of Nebraska tractor test archive, and public auction records. Wear items come from long-time owners and restorers. Where sources disagree, we say so.