Whether it's a 1940 K-1 or a 1979 Merc 2000, the identification of a Mercury Kiekhaefer outboard motor depends more on the Model Number than on any other factor, including appearance. From 1941 to 1957, Mercury also built "Wizard" motors for Western Auto that closely resembled the Kiekhaefer motors, but the Wizard motors had different model designations, unique to the brand, and slight differences prevent the the parts from being interchangeable with those of the Mercury Kiekhaefer motors.
Look on the top of the sheave (the pulley-like attachment around which you wrap the starter rope) for a model number, K1, K2, K3, K4 or K5, stamped into the metal. The "K" numbers are Mercury Kiekhaefer motors. The Wizard motor, though similar in appearance, didn't appear until 1941, and those serial numbers begin with "WA".
From 1941 to 1946, the model number, beginning with the letters, "KB," is stamped on a plate riveted just below the powerhead (the internal combustion part of the outboard) to the starboard (right) side of the motor's leg (the part that goes down toward the water)
Models built from 1947 to 1955 have an instruction plate riveted to the front of the engine with the model number stamped on it. Likewise, 1949 to 1953 four-cylinder models have an instruction plate, with the model number stamped on it, riveted to the cover on the front of the engine.
Mark 6 and 6A motors, made from 1956 through 1959, have their model number stamped on the swivel bracket, just below the powerhead (the internal combustion engine at the top of the motor). If the ID plate is in front, just below the motor cover, and the motor has four cylinders, it's probably a Mark 30, built between 1956 and 1958.
If the motor is any other model, the model number is stamped on a plate across the front or back of the swivel bracket, just below the power head.
- Remember: "K" models were built between 1940 and 1952. In 1953, the "Mark" models appeared and were built until 1960. In 1960, the "Merc" models of the Kiekhaefer appeared and lasted until 1979.
- If the plate is missing, casting numbers on the cylinder block or numbers stamped into the carburetor may help narrow the age down somewhat.
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