How to Mount an Outboard Motor

Updated February 21, 2017

Outboard motors continually increase in both horsepower and size. Larger outboard motors require a strong connection between the motor mount and a boat transom. A transom contains reinforcements that accommodate the outboard motor. When installing an outboard to the transom, use a motor that does not exceed the horsepower or weight limit posted on your boat's capacity rating placard. Exceeding the horsepower rating can cause damage to the transom.

Measure between the widest points of the transom with a tape measure and mark half the measurement on the transom with a wax marker. Repeat the process to place a centre mark at the lowest point of the transom.

Align a level with the two marks. Draw a vertical line to connect the points with a wax marker.

Refer to the chart mounted on the motor to determine the mounting height of the outboard motor.

Align the top of the mounting template with the height required by the outboard. Slide the template to align the centre of the template with the centre line drawn on the transom. Secure the template to the transom with masking tape.

Read the hole requirements printed on the mounting template. Secure the drill bit specified on the template in the chuck of a drill motor. Drill one hole at each marked located on the template. Remove the template from the transom.

Remove the cowling from the top of the outboard motor.

Connect the hook from an engine hoist to the lifting eye install on the top of the outboard motor. Pump the handle of the engine hoist top lift the motor. Push the engine hoist to the transom.

Align the holes in the mounting bracket attached to the outboard with the holes you drilled in the transom.

Slide one mounting bolt through each hole in the mounting bracket and each hole drilled in the transom. Slide a washer and lock washer over each bolt. Thread a nut onto each bolt.

Tighten each bolt with a properly sized socket attached to a 1/2-inch ratchet handle.


Overtightening the mounting bolts could crush the transom.

Things You'll Need

  • Tape measure
  • Wax marker
  • Level
  • Masking tape
  • Drill bit
  • Drill motor
  • Engine hoist
  • Socket set
  • Thread locking compound
  • 1/2-inch ratchet handle
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