How to Decode the Model Number on a Johnson Outboard Motor

Written by will charpentier
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How to Decode the Model Number on a Johnson Outboard Motor
Johnson and Evinrude, both products of OMC, used the same system. (toy outboard motor image by pearlguy from

The model number of a Johnson outboard motor can deliver a wealth of information, telling you the horsepower of the motor, its design features, the length of the driveshaft, and even when it was built. It's a tool that some old-timers use to impress new guys. When someone is looking for information on a motor with the model number "J9.9FRM-ED", an old boater with a quick memory can say that it's a Johnson 9.9 horsepower motor that has a pull-rope recoil starter with a 15-inch driveshaft, without a hydraulic tilt and trim system, built in 1996.

Skill level:


  1. 1

    Read the model number from left to right. The first part of the model number is a letter, either "J" for Johnson or "E" for Evinrude. The length of the model number isn't fixed; it varies, since the manufacturer uses the code to distinguish one model from others with similar features.

  2. 2

    Look at the second part of the number. This will be 1, 2, or 3 digits, indicating the horsepower.

  3. 3

    Find the letter at the end of the horsepower number. The letter "C" means "Counter Rotation", "D" means "Remote Electric" start, "E" means "Electric Start with Remote Steering", "FA" denotes a four-stroke motor, "FE" indicates a four-stroke with an electric tiller and "FR" indicates a four-stroke motor with a rope starter.

  4. 4

    Double-check the design features: the letter "I" means the motor has Ficht fuel injection, "J" is a jet drive, "K" is a three-cylinder motor of 25 to 35 horsepower, and "M" is a manual-tilt, electric starter-equipped motor. "MS" stands for a manual-tilt, electric-start, "special" motor.

  5. 5

    Look for special characteristics in the design features part of the model number. The letter "N" is another designation for a counter rotating motor--half of a matched pair of motors with propellers that turn in opposite directions, "P" says the motor comes equipped with power steering, The letter "Q" is found on a three-cylinder 25 to 35 horsepower motor with tilt and trim.

  6. 6

    Find the letter "R" in the third position and you know the motor is a rope-start motor that uses a pull-rope and recoil starting unit. The letters "RW" mean the motor was built for commercial use and "SL" means the motor is a 60-degree V-type motor with tilt and trim.

  7. 7

    Look at the fourth position of the model number, the driveshaft length. A blank space indicates a 15-inch driveshaft, the letter "L" stands for a 20-inch shaft, "Y" stands for a 22.5-inch shaft, "X" a 25-inch shaft and "Z" for a 30-inch driveshaft.

  8. 8

    Observe the final position of the model number that was once jibberish: It contains the year the model was built. Each letter indicates a number--"I" stands for "1", "N" stands for "2", "T" stands for "3", "R" stands for "4", "O" stands for "5", "D" stands for "6", "U" stands for "7", "C" stands for "8", "E" stands for "9" and "S" stands for "0". A Johnson outboard motor with "ED" in the last position of its model of its model number was produced in "96", or 1996.

Tips and warnings

  • You'll find the model number stamped into a silver core plug on the top of the motor's power head.
  • Not all model numbers are the same length. Early Johnsons had a two-letter, two-number alphanumeric model code. The model MD-15 is an example: "M" stands for the model year (1940) and "15" means it has 1.5 horsepower. There's no amplification beyond that. There's no "J" prefix because Johnson hadn't been absorbed by Evinrude. Even today, a model number will vary in length, since the descriptive sub-codes may be one or two letters, or a blank space. Some model numbers may not mention all features, or favour one feature over another (if "FR", four-stroke rope start, appears, "R" won't be repeated in the next position to indicate that it's a rope start motor)
  • As an example of today's coding, a model number "J9.9FRM-ED" is a Johnson ("J") 9.9 horsepower ("9.9") four-stroke, equipped with a rope starter ("FR"), that must be tilted manually ("M"); the dash ("-") means that the driveshaft is 15 inches long and the "ED" is the date code for "96", meaning the motor was built in 1996.
  • If, as you read the model number, you look for, and touch the feature specified in the model number (if possible--you can't "touch" the horsepower rating or the year built), you'll have a better understanding of your motor's capabilities and limits.

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