Mercury Marine FourStroke 75–150 hp service schedule
Outboard ·
13 maintenance items for the Mercury Marine FourStroke 75–150 hp. The engine oil is changed every 100 h or 12 months. When an item has both an hour and a calendar interval, the one that comes first applies.
| Item | Engine hours | Calendar | Rule |
|---|---|---|---|
| Before each use: oil level, cowl and lanyard, propeller, cooling tell-tale after starting | — | before each use | |
| After each use in salt or brackish water: flush the cooling systemAfter every saltwater run. | — | before each use | |
| Break-in service: engine oil and filter, gearcase lubricantOnce, after break-in. | at 20 h, once | — | |
| Change the engine oil and the oil filter | every 100 h | every year | whichever first |
| Change the gearcase lubricant | every 100 h | every year | whichever first |
| Replace the fuel filter element | every 100 h | every year | whichever first |
| Lubricate the grease points (steering, tilt tube, propeller shaft) | every 100 h | every year | whichever first |
| Inspect the spark plugs | every 100 h | every year | whichever first |
| Inspect the sacrificial anodes; replace when half wasted | every 100 h | every year | whichever first |
| Inspect the propeller and the shaft seal | every 100 h | every year | whichever first |
| Replace the water pump impeller | every 300 h | every 3 years | whichever first |
| Replace the spark plugs | every 300 h | every 3 years | whichever first |
| Inspect the thermostats | every 300 h | every 3 years | whichever firstDealer |
Free in Voydar Helm: each interval becomes a maintenance task, due by hours or by date, whichever comes first.
Source
Read from summaries of the maker's manual, not the manual itself.
Revision read: Mercury Dockline “Four-stroke maintenance” and partsvu.com schedule summary, read 2026-10-12. Confirm against the manual for your model year and serial number.
Reference only. Intervals vary by serial number, use and climate; your engine's current manual and your dealer are the authority. Part numbers and diagrams are in the manual.