Vintage Tecumseh Identification
Article by Mark Trotta
There are several visual cues to "ballpark" the year of an old Tecumseh small engine. Up until the mid seventies, gas tanks were metal. After that, gas tanks were plastic.
Pictured: 1968 Tecumseh H25
Early Tecumseh engines (up until mid-1970's) have a metal identification plate on the blower housing, held on by two rivet-screws. Later engines have stamped, or embossed numbers in the blower housing.
Engine Model Codes
- H = Horizontal Shaft
- HS = Horizontal Small Frame {engine}
- HM = Horizontal Medium Frame {engine}
- HHM = Horizontal Heavy Duty {cast iron} Medium Frame {engine}
- HH = Horizontal Heavy Duty {cast iron}
- V = Vertical Shaft
- LAV = Lightweight Aluminum Vertical {engine}
- VM = Vertical Medium Frame {engine}
- TVM = Tecumseh Vertical {medium frame}
- VH = Vertical Heavy Duty {cast iron}
- TVS = Tecumseh Vertical Shaft
- TNT = Toro N' Tecumseh
- ECV = Exclusive Craftsman Vertical
- OVM = Overhead Valve vertical Medium Frame {engine}
- ECH = Exclusive Craftsman Horizontal
Engine Identification Plate
The first line on the ID tag, the word "MODEL" appears. In our example, the "H" denotes horizontal-shaft engine. The numbers after the letter indicate horsepower. For example, an H25 was 2-1/2 horsepower, an H30 was 3 horsepower, etc.
Following that is a group of numbers that tells you the sub-model within the H25 family.
Manufacture Date
The second line on the identification tag starts with "SERIAL" followed by four numbers. These tell you the date of manufacture.
The first digit will be the last digit of the year. For example, "8" could mean either 1968 or 1978, but since the H25 was not made after 1974, that identifies this engine as a 1968 production. The next three numbers are the calendar day of the year. Since 1968 is not a leap year, 275 is October 2nd. That means this H25 Tecumseh engine was produced on October 2nd, 1968.
The last set of digits on the ID tag is the engine's unique serial number.
Missing ID Tag
You may have an early Tecumseh engine whose ID tag is missing. To help determine what year and model engine it is, you may need to remove the cylinder head and measure the cylinder bore and stroke. But there are a few ways you can "ballpark" what year it is.
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Sometimes you can tell the approximate age of an engine by a decal type. Tecumseh affixed several styles of logos to their engine's blower housing. But due to the passing of time, the decals are often no longer there or visible.
Points vs Electronic Ignition
Another way to determine the approximate year of the motor is by the ignition system. Tecumseh first offered a capacitor discharge ignition in 1968 on their cast-iron engine models. Around 1976, electronic ignition became standard equipment on vertical-shaft engines (such as lawn mowers, etc).
Read: Tecumseh Points Ignition Repair
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Engine Colors
Most old Tecumseh engines were painted either red, white, or black.
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Starter Housing
Early Tecumseh engines have "teardrop" shaped starter housings, which are metal and attach to the blower housing with four rivets.
Later engines had "stylized" starter housings with thin slots arranged in a circle.
The plastic gas tank on this purple motor tells us it's a late 1970's or newer.
The muffler helped identify this motor as a 1981 H35 model.
Tecumseh Side Popper
The "side popper" nickname was given to Tecumseh engines that had side exhaust instead of rear exhaust. These were seen during the 1970's on gas-powered lawn equipment as well as several brands of mini-bikes.
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Related Articles:
Vintage Tecumseh Engine Build
Tecumseh Crank and Connecting Rod Inspection
Integral Valve Seat Repair
Tecumseh Carburetor Replacement
Tecumseh Points Ignition Repair
