How to Hook a Timing Light to an Outboard

by Kyle McBride

Overview

Ignition timing lights are a good tool to use to verify that each plug is getting power from its coil. With access to the crankshaft position indicator, the timing light can indicate whether the plugs are firing at the right time or if they are off a few degrees. Ignition timing is crucial to developing proper horsepower while minimizing free hydrocarbons, or unburnt fuel, in the exhaust stream.

Step 1

Remove the engine cover fully from the motor. Immerse the foot of the outboard in a water barrel, or install the water earmuffs onto the intake ports on the foot of the motor and hook them up to a garden hose with the water turned on.
Step 2

Start the engine and run it at idle speed. Clip the power lead on the timing light onto the battery positive lug on the starter solenoid to power the light.
Step 3

Clip the timing light's inductive pickup around a spark plug wire. Pull the trigger on the timing light and verify that the light is flashing. Repeat this step on each spark plug wire to verify that the wires and coils are delivering power to the plugs.

References & Resources