How to Time an Outboard Motor

A properly timed outboard doesn't sputter, hiccough or sneeze -- it purrs, quietly. While more and more outboard engines are controlled by a small, onboard computer, older outboards still require a timing check as part of the annual tuneup. Performing the tuneup ensures better performance and fuel efficiency, and helps prolong the outboard's service life. It also helps lengthen the time between major overhauls, meaning a properly timed outboard saves you money in more than one way.

Things You'll Need

  • Clamp-type shop tachometer
  • Timing light
  • Outboard flushing attachment
  • Garden hose
  • Pliers
  • 1 1/16-inch wrench
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Instructions

    • 1

      Turn off the outboard motor. Open the clamp of the clamp-type tachometer. Fit the clamp around the spark plug wire powering the spark plug in the No. 1 cylinder.

    • 2

      Push the rubber cover at the end of the No. 1 spark plug wire upward to expose the contact at the top of the plug's insulator. Clamp the lead of a timing light to the contact.

    • 3

      Fit an outboard flushing attachment to the water intakes of the outboard. Thread a garden hose into the flushing attachment and turn the water on.

    • 4

      Start the engine. When it warms to its normal temperature at idle, shift the engine into "Forward." Raise the motor's speed to 4,500 rpm and aim the timing light. Consult the owner's manual for your outboard for the correct timing. Aim the timing light at the timing pointer. If the timing advance indicated in your owner's manual appears, your timing is correct and requires no further adjustment. If, when you aim the timing light at the timing pointer, another number appears, your timing requires adjustment.

    • 5

      Shut the outboard off. Free the ball joint of the spark control rod from the ball joint of the spark lever cam by unsnapping it with pliers, if the timing requires adjustment. Two revolutions of the spark control rod change the timing by 1 degree. Turn the rod clockwise to advance and counterclockwise to retard the engine's timing.

    • 6

      After you complete the adjustment, snap the ball joint of the spark control rod into the ball joint of the spark lever cam. Restart the outboard and check the timing again. Readjust the timing as often as necessary to achieve the right spark advance.