How to Troubleshoot a Yamaha Outboard Alarm

by Will Charpentier

The Yamaha outboard alarm system can fail just like any other system on your outboard. Troubleshooting the alarm system includes making sure the horn associated with the alarm works, making sure the warning light comes on and the horn sounds when the oil level drops below acceptable levels and ensuring the warning sounds if the engine overheats. You can even perform the alarm system tests while you are boating

1. Turn the ignition key to the start position and pull the safety lanyard. If the horn is operative, it will sound.

2. Disconnect the pink lead and black lead from the temperature warning sensor on the powerhead. Plug the black lead into the socket for the pink lead. The temperature warning icon should flash and the horn should sound.

3. Place a clean container large enough to hold the contents of the engine's oil reservoir below the oil reservoir. Remove the glass sight tube from the oil reservoir and drain the reservoir into the container.

4. Start the engine. When the oil goes below the "Add Oil" level, the alarm should sound. Turn the engine off when the alarm sounds, to avoid operating the engine with low oil.

Items you will need

  • Clean container


  • Never operate your outboard out of the water unless you provide a source of cooling water. Use the motor's flushing port or connect a flushing attachment to a garden hose and placing the attachment over the cooling water inlets. You may also immerse the motor in a motor test tub filled with water so that the cooling water inlets are submerged.


  • "Yamaha Outboards Repair Manual 2.5 - 250 HP 2-Stroke, 1997-1999"; Seloc Marine, 2007

About the Author

Will Charpentier is a writer who specializes in boating and maritime subjects. A retired ship captain, Charpentier holds a doctorate in applied ocean science and engineering. He is also a certified marine technician and the author of a popular text on writing local history.