Go by both engine hours and the calendar
The engine should be serviced when the first limit in the manual is reached, either hours or time. So an engine that has barely been run still needs service. The table below is based on individual manuals, and another model from the same brand may have a different schedule. Honda and older Tohatsu have shorter calendar intervals than the usual annual service.
Find out the exact model and serial number before you book. In the engine catalogue you will find manuals and model families.
Intervals by brand
| Manual | First service | Recurring service |
|---|---|---|
| Yamaha F115A/F150A, 2012 | 20 hours/3 months | 100 hours/1 year. Other jobs have longer intervals |
| Mercury 15/20 EFI FourStroke, 2019 | Daily checks and break-in as per manual | 100 hours/1 year. Extended work after 300 hours/3 years |
| Suzuki DF15A/DF20A, 2012 | 20 hours/1 month | 100 hours/12 months in the basic schedule |
| Honda BF8D to BF20D, manual 00X31ZY06520 | 20 hours/1 month | 100 hours/6 months, plus annual and longer intervals |
| Tohatsu MFS4B/5B/6B | 20 hours/1 month | 50 hours/3 months and 100 hours/6 months for different tasks |
On Mercury engines, engine oil, oil filter and gearcase oil are changed at 100 hours or once a year.
Not all parts are replaced at the same time
The schedule distinguishes between inspection, adjustment and replacement. Oil filter, gearcase oil, spark plugs, fuel filter, impeller and timing belt often have different intervals. Suzuki's manual says the low-pressure fuel filter should be inspected after 100 hours/12 months and replaced after 200 hours/2 years. So when an ad says “full service”, you don't know which parts were replaced.
Ask for an invoice showing the date, engine hours and work done. If you service the engine yourself, keep receipts and notes with the engine's paperwork.
Hard use calls for more frequent maintenance
The basic schedule assumes normal conditions. Salt water, dirty water and hard running mean more frequent checks and lubrication. Flush the engine as the manual describes after every trip, however often it goes in for service. If you run in conditions other than those the manual assumes, talk to an authorised dealer.
Winter storage has its own steps, and an oil change is no substitute for frost protection. Read more about winter storage of outboards.
Make a service plan for your engine
- Photograph the identification plate and find the right edition of the manual.
- Note the last service, actual hours and what was done.
- Set a date for the next time for each task separately.
- Ask the workshop to list what gets replaced, what only gets checked and what the materials cost.
- Fix faults before your next trip.
Then compare service prices for the same job. A cheaper quote sometimes includes fewer tasks.
Frequently asked questions
Does the table apply to all engines from the brand?
No. Each row comes from a specific manual. Your model, serial number and market may have a different schedule.
Do I need to service it if I've only run it a little?
Yes. When the calendar limit is reached it's time, even if you haven't reached the hours.
Is an inspection the same as a replacement?
No. The manual states for each part whether it should be checked, adjusted or replaced. Ask the workshop to write down what was done.
Sources
- Yamaha F115/LF115/F150/LF150, underhåll s. 82 till 89 yamahamotor-as.custhelp.com
- Mercury 15/20 EFI FourStroke, 8M0165094, underhåll s. 91 till 93 servicelit.mercurymarine.com
- Suzuki DF15A/DF20A, underhåll s. 41 till 49 suzuki-marine.gr
- Honda BF8D till BF20D, schema s. 72 till 73 cdn.powerequipment.honda.com
- Tohatsu MFS4B/5B/6B, schema s. 37 tohatsu.com