An outboard ignition switch is the key switch on the dash or remote control box that turns the engine’s electrical system on, cranks the starter and, on most engines, stops the engine by grounding the ignition when you turn it off. When it fails, the engine may not crank, may cut out over bumps, or may not shut off with the key. Switches and their wiring differ between engine makers, so a replacement must be the type made for your engine brand.
Positions and push-to-choke
Most switches have OFF, RUN and START. Many carbureted engines with remote controls also use push-to-choke: pushing the key in while starting works the choke or enrichment. Fuel-injected engines usually do not need it.
Ignition switch problems
- No crank when turned to START. Worn contacts, a loose terminal or a corroded connector at the back of the switch.
- Engine cuts out over bumps. A worn switch or loose connection briefly breaking the run circuit, or grounding the stop circuit.
- Engine will not shut off. A failed stop circuit in the switch or its wiring; fix this before using the boat again.
- Gauges dead with the key on. A failed switch or a blown fuse feeding it.
Check these first
- The kill switch clip or lanyard is in place; see outboard kill switch.
- The battery is charged and the battery switch is on; see boat battery switches.
- The engine’s main fuse is intact and the harness plug between the boat and engine is tight and dry.
Testing the switch
Disconnect the battery, unplug the switch and check continuity between its terminals in each key position with a multimeter, comparing the results with the switch diagram in your engine’s service manual. Terminal labels and wire colors differ between engine makers, so use the diagram for your engine, not a generic one.
Replacing it
- Disconnect the battery.
- Label each wire before removing it, or photograph the back of the switch.
- Fit the replacement made for your engine brand, connecting each wire to the matching terminal.
- Fit the weather boot or cap so spray cannot reach the switch.
- Test START, RUN, the stop function and the kill switch before leaving the dock.
Keep water out
Corrosion is the main enemy. Keep the key boot in place, spray the terminals with a marine corrosion inhibitor, and check the switch when you service the engine.
Related
For a no-start, see outboard won’t start; for gauges, outboard tachometers. Browse engines on outboard motors.
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