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What each manufacturer’s manual says is due and when, with the model, edition and page for every table.
These are the manufacturers' published schedules for normal use, copied from their owner's manuals and linked so you can check each line. Heavy use and saltwater use call for more frequent service, and your own engine's manual governs, not this page. Break-in periods differ by make, so the first service is listed separately for each. Where a manual says "whichever comes first," it means whichever arrives first, the hours or the calendar interval. An engine that runs 40 hours a year is due on the calendar, not the hour meter.
Each section states the manufacturer source and the models it covers. If your engine is not named, do not assume the listed intervals apply to it. We left out intervals we could not trace to a manufacturer source.
Two Mercury manuals are covered. The 150 FourStroke (3.0 L) is from Outboard Operation, Maintenance, Warranty, Installation Manual 8M0105247, April 2015, "Inspection and Maintenance Schedule," printed pages 60 to 62. The V6 (175-225) and V8 (200-300) models are from Operation and Maintenance Manual 8M0140581, December 2017 (copyright 2018), printed pages 75 to 77. Mercury's rule as printed is "every 100 hours of use or once yearly, whichever occurs first" and "every 300 hours of use or three years."
Swipe sideways to see every column.
| Item | 150 FourStroke (2015 manual) | V6 175-225 and V8 200-300 (2017 manual) |
|---|---|---|
| Engine oil and filter | Every 100 hours or once yearly, whichever occurs first. Change more often under adverse use such as extended trolling. | Same |
| Gearcase lube | Drain and replace every 100 hours or yearly | Same |
| Spark plugs | No replacement interval printed (decal icon only). Saltwater: at 100 hours or yearly, remove and put anti-seize on the threads only. | Replace every 300 hours or 3 years. Saltwater: at 100 hours or yearly, remove, inspect for corrosion, replace as necessary, anti-seize on the threads. |
| Fuel filter | Check the low-pressure filter at 100 hours or yearly, replace if required | Check the engine-mounted water-separating filter and the boat-mounted filter at 100 hours or yearly. Drain or replace if required. |
| Water pump impeller | Replace every 300 hours or 3 years, sooner if overheating or reduced water pressure | Same, dealer service |
| Thermostat | Inspect visually at 100 hours or yearly (corrosion, broken spring, closes at room temperature), dealer service | Same |
| Anodes | Check at 100 hours or yearly, more often in saltwater | Same |
| Propeller shaft and splines | Not in the 150 schedule. Upper driveshaft splines: lubricate every 300 hours or 3 years (dealer). | Remove the propeller and lubricate the propeller shaft every 100 hours or yearly. Upper driveshaft splines every 300 hours or 3 years (dealer). |
| Belts | No timing belt or chain interval printed. Alternator drive belt: replace every 300 hours or 3 years. | Same |
| Power trim fluid | Check at 300 hours or 3 years | Same |
Neither manual prints a break-in or first-service entry, and neither prints a valve clearance entry. Both say to flush after each use in salt, polluted or muddy water, and to wash off salt and inspect the powerhead for salt buildup after each saltwater use. Verado and the 75-115 FourStroke are not covered here. Their manuals did not surface from Mercury's own library, and the 150 manual's schedule is printed for the 150 only.
From 4.5L and 6.2L MPI Operation and Maintenance Manual 90-8M0128973, May 2017, "MerCruiser Gas Sterndrive Inspection and Maintenance Schedule," printed pages 44 to 46. The break-in is in the Getting Started section, "20 Hour Break-In Period."
Swipe sideways to see every column.
| Item | Interval (4.5L and 6.2L MPI, 2017 manual) |
|---|---|
| Break-in | First 20 hours. Do not run below 1500 rpm for long periods in the first 10 hours. Stay at or under 3/4 throttle in the first 10 hours. Use occasional full throttle in the next 10 hours. A new sterndrive may need up to 470 mL (16 fl oz) of gear lube added during the 20 hours as air purges. |
| Engine oil and filter | Annually or 100 hours |
| Sterndrive gear oil | Annually or 100 hours |
| Propeller shaft splines | Lubricate annually or 100 hours |
| Water-separating fuel filter | Replace annually or 100 hours |
| Engine coupler | Lubricate every two months or 50 hours, and again annually or 100 hours. Idle or trolling use: every 50 hours. |
| Anodes | Inspect weekly, and inspect again annually or 100 hours |
| Spark plugs and wires | Inspect every three years or 300 hours. If good, repeat the inspection every 100 hours or yearly. Replace as necessary. |
| Seawater pump | Inspect and replace worn components every three years or 300 hours (dealer). No fixed impeller replacement interval is printed. |
| Accessory drive belt | Inspect annually or 100 hours (dealer) |
| PCV valve | Replace annually or 100 hours |
| Antifreeze (closed cooling) | Replace at five years or 500 hours, or every two years if not extended-life antifreeze |
The timing belt, valve clearance and thermostat are not in this schedule. For brackish or saltwater use, the manual says to flush the engine with fresh water after each use and to check the seawater inlets, strainer, coolant level and anodes weekly.
Honda's chart sits on printed pages 61 and 62 of the first two manuals and pages 67 and 68 of the BF150A manual. The manuals are 00X31ZY36020 for the BF200A and BF225A (copyright 2017, serial numbers BAEJ and BAFJ 1800001 and up), 00X31ZX26120 for the BF250A (copyright 2017, serial numbers BBJJ 1000001 and up, table identical to the BF200A and BF225A) and 00X31ZX16260 for the BF150A (serial numbers BANJ and BAPJ 1400001 and up). These are Honda Marine's US and Canadian models. Honda states: "Perform at every indicated month or operating hour interval, whichever comes first." The columns are the first month or 20 hours, every 6 months or 100 hours, every year or 200 hours, every 2 years or 400 hours and every 6 years or 1,200 hours.
Swipe sideways to see every column.
| Item | BF200A, BF225A and BF250A | BF150A |
|---|---|---|
| Engine oil | Change at 1 month or 20 hours, then every 6 months or 100 hours | Same |
| Oil filter | Replace every year or 200 hours | Same |
| Gear case oil | Change at 20 hours, then every 100 hours or 6 months | Same |
| Spark plugs, standard | Check-clean or replace every 6 months or 100 hours | Check-adjust or replace every 6 months or 100 hours |
| Spark plugs, optional iridium | Check every year or 200 hours. Replace every 2 years or 400 hours. | Same |
| Fuel filter, low pressure | Check each use and every 100 hours. Replace every 2 years or 400 hours. Water separator: check each use and every 100 hours. | Water separator: check each use. Low-pressure filter: check at 100 hours, replace every 2 years or 400 hours. |
| Fuel filter, high pressure | Check at 100 hours. Replace every 2 years or 400 hours (dealer). | Replace every 2 years or 400 hours (dealer) |
| Water pump, housing and impeller | Check every year or 200 hours (dealer). The chart prints no replacement interval. | Water pump: check every year or 200 hours |
| Thermostat | Check every year or 200 hours (dealer) | Same |
| Anodes | Outside: check each use. Inside (sleeve, exhaust manifold): check every 2 years or 400 hours. V-bank bottom: replace at 6 years or 1,200 hours. Replace when about two-thirds consumed or crumbling. | Outside: check each use. Inside: check every 2 years or 400 hours. Replace when down to about one third of original size or crumbling. |
| Propeller shaft and grease points | Grease at 20 hours, then every 100 hours. Lubricate more frequently when used in salt water. | Same |
| Timing belt | Check-adjust every year or 200 hours (dealer) | No timing belt line in the BF150A chart |
| Valve clearance | Check-adjust every year or 200 hours (dealer) | Same |
On the water pump, Honda's chart lists a check every year or 200 hours and prints no impeller replacement interval. We do not state one. The first service is the 1 month or 20 hour column. For professional commercial use, Honda says to log hours of operation to determine proper maintenance intervals. Flush with clean water after each use in salt, turbid or muddy water. Honda also notes that a warranty claim is not denied merely for missing the schedule, but a part that fails from lack of maintenance is not covered.
Yamaha's US owner's manuals are behind a serial-number lookup, so we could not read a US edition. These intervals come from Yamaha Motor Europe's owner's manuals, which are official Yamaha PDFs in Danish and Norwegian. We translated the chart headings and the numbers and symbols are the same in any language. US intervals may differ, so check your manual before you quote or rely on this table. The manuals are 6P2-28199-8L-K0 for the F200C, F225B and FL225B (Danish, chart 1 on printed pages 70 to 72, chart 2 on page 73) and 6CE-28199-82-N0 for the F225F, F250D and F300B (Norwegian, chart 1 on printed pages 74 to 76, chart 2 on page 76, greasing on page 77). Neither edition is dated in its text. Both give the same schedule for the items below, and the chart assumes 100 hours of use per year and regular flushing.
Swipe sideways to see every column.
| Item | Chart entry (F200C/F225B and F225F/F250D/F300B) |
|---|---|
| Engine oil | Replace at 20 hours (3 months), then 100 hours (1 year) |
| Oil filter (cartridge) | Replace at 100 hours (1 year) |
| Gear oil | Replace at 20 hours (3 months), then 100 hours (1 year) |
| Spark plugs | Inspect, replace as needed at 100 hours (1 year). The chart prints no fixed replacement hour figure. |
| Fuel filter (removable, on engine) | Inspect, replace as needed at 20 hours and 100 hours |
| Water pump impeller and housing | Inspect, replace as needed at 100 hours (1 year). Replace at 300 hours (3 years). |
| Thermostat | Inspect, replace as needed at 100 hours (1 year) |
| Anodes, external | Inspect, replace as needed at 100 hours (1 year) |
| Anodes, internal (cylinder head, block, thermostat cover, oil cooler cover, exhaust guide) | Replace at 500 hours (5 years). The F200C/F225B manual also shows a cylinder head anode inspected at 100 hours. |
| Propeller shaft and other grease points | Grease at 20 hours and 100 hours. The propeller shaft takes Yamaha Grease D (corrosion resistant). |
| Timing belt | Inspect, replace as needed at 100 hours (1 year). Replace at 1,000 hours (chart 2), which has no calendar pairing. |
| Valve clearance | Inspect and adjust at 500 hours (5 years) |
The 20 hour (3 month) column is the first service. The manual defines severe use as sustained full throttle or low rpm for many hours, no warm-up or cool-down time, frequent rapid acceleration and shifting, frequent starts and stops, or alternating light and heavy loads, and says to service at double the frequency, for example 25 hours instead of 50. After use in salt, mud or turbid water, flush with clean water after every trip. With leaded or high-sulfur fuel, check valve clearance more often than every 500 hours. The Yamaha F150 is not covered here, because no sourced chart was available for it, so do not assume the V6 table applies to it.
This section is partial. The table is from Suzuki Marine Australia, Service and Maintenance, a web page rather than a manual, so there is no manual edition or page number. Suzuki's DF150 to DF300 owner's manuals exist, but we could not open them to read the periodic maintenance table.
Swipe sideways to see every column.
| Item | Interval (partial) |
|---|---|
| Engine oil | Initial 20 hours, then every 100 hours or once a year |
| Engine oil filter | After 20 hours, then once a year |
| Gear oil | After 20 hours, then every 100 hours or once a year |
The page says the full schedule is explained in your owner's manual. Spark plugs, fuel filters, impeller, thermostat, anodes, timing chain, valve clearance and propeller shaft grease are not sourced here, so we do not list them. Get the full schedule from your Suzuki owner's manual or your dealer.
Not covered. Volvo Penta serves its operator manuals and service protocols only through a serial-number lookup, and we could not reach a document to source any interval. We list none rather than guess.
How often should a Mercury 150 be serviced?
Per the 2015 manual for the 150 FourStroke, engine oil and filter and gearcase lube are
due every 100 hours or once yearly, whichever occurs first. The impeller is due every 300
hours or 3 years.
What is a 100 hour service?
It is the service stage many manuals tie to 100 hours or one year. Mercury, Honda,
Yamaha and MerCruiser each list engine oil and gear oil there, but the other items differ
by make, so use the table for your engine and your own manual. Honda's chart uses 100
hours or 6 months for engine oil.
When is the first service on a new outboard?
Honda lists the first month or 20 hour column. Yamaha's chart starts at 20 hours (3
months). Suzuki's Australian page gives an initial 20 hour oil change. The two Mercury
outboard manuals we read print no break-in entry, so follow your manual.
How often does a Honda outboard water pump impeller need replacing?
Honda's chart for the BF150A, BF200A, BF225A and BF250A lists a check every year or 200
hours and prints no replacement interval.
What is the MerCruiser break-in?
For the 4.5L and 6.2L MPI, the first 20 hours. Do not run below 1500 rpm for long periods
in the first 10 hours, stay at or under 3/4 throttle in that time, and use occasional full
throttle in the next 10 hours.
What does "whichever comes first" mean?
Service is due at the hour figure or the calendar date, whichever arrives first. Honda
prints this wording directly, and Mercury prints "whichever occurs first."
A boat with several engines and a generator has several maintenance clocks. YachtGrade tracks maintenance for each piece of equipment by running hours and calendar date, whichever comes first, and shows what is due next. Upload a manual and YachtGrade can propose service intervals for a person to review and confirm before they are added. See how maintenance tracking works, the boat maintenance log, and how many hours is a lot on a boat engine.
Mercury: 8M0105247 (April 2015) and 8M0140581 (December 2017). MerCruiser: 90-8M0128973 (May 2017). Honda Marine: 00X31ZY36020, 00X31ZX26120 and 00X31ZX16260. Yamaha Motor Europe: 6P2-28199-8L-K0 and 6CE-28199-82-N0. Suzuki Marine Australia: Service and Maintenance. Checked 4 October 2026.
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These are manufacturers’ published schedules for normal use. Your engine’s own owner’s manual governs. This is general guidance, not a survey.
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