100-Hour Outboard Maintenance
Why it matters, and what is included.
Engine makers call for service every 100 hours or once a year because that matches real-world wear, especially in salt water like Hawaiʻi's.
What is typically included
- Engine oil and filter on four-stroke engines.
- Gear case (lower unit) oil, with new drain and vent plug gaskets.
- Fuel filters inspected or replaced.
- The cooling system checked, including the water pump and thermostat.
- Battery and charging system tested.
- Grease points done and the propeller shaft cleaned and greased.
- A computer scan for stored fault codes on engines that support it.
Exactly what is due depends on your engine and its hours. Our engine service guides show the factory schedule for over 160 models.
How often in Hawai‘i?
Every engine here runs in warm salt water, so our standard is a full yearly service every 200 hours or 1 year, whichever comes first, with the water pump impeller replaced each time. If you run a lot of hours, the maker's 100-hour service goes in between. New engines need their first (break-in) service, usually at 10 to 20 hours.
Why annual service matters even with low hours
Engines that sit often suffer more than engines that run. Moisture gets into fuel and the gear case, and fuel keeps breaking down while the boat is idle. A yearly service sets a baseline and prevents surprises on the water.
