The Complete Boat Maintenance Guide
From bass boats to center consoles, pontoons to ski boats, this guide covers outboard and inboard boat engine maintenance along with hull and trailer care. Whether you run a Mercury, Yamaha, Honda, Suzuki, or Evinrude outboard, or a MerCruiser or Volvo Penta sterndrive, we have your maintenance covered. We include engine oil and filter changes, lower unit gear oil, impeller and water pump service, fuel system and ethanol treatment, spark plug replacement, prop inspection, battery care, hull cleaning, zinc anode replacement, and end-of-season winterization. Select your water type below. Salt water demands shorter intervals and extra corrosion protection.
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Intervals Based on Manufacturer Recommendations
These intervals are compiled from Mercury, Yamaha, Honda, and other marine engine manufacturer service manuals. Salt water use requires shorter intervals across the board. Always cross-reference with your owner's manual for model-specific requirements. For personalized reminders, download LookOver free on iOS and Android.
| Service Task | Pre-Launch Every trip | 25 Hours Regular | 50 Hours Service | 100 Hours Major | Annual Winterize |
|---|---|---|---|---|---|
Visual inspection of hull and hardware | - | - | - | - | |
Check engine oil level | - | - | - | - | |
Check coolant level (inboard) | - | - | - | - | |
Check battery voltage and connections | - | - | - | - | |
Verify safety equipment on board | - | - | - | - | |
Confirm drain plug installed | - | - | - | - | |
Change engine oil (4-stroke) | - | ||||
Check lower unit gear oil level | - | - | - | ||
Inspect fuel system and lines | - | - | |||
Inspect propeller for damage | - | - | |||
Change engine oil and filter | - | - | |||
Change lower unit gear oil | - | - | |||
Replace fuel filter / water separator | - | - | |||
Inspect water pump impeller | - | - | - | ||
Check spark plugs | - | - | - | ||
Inspect belts and hoses (inboard) | - | - | |||
Replace water pump impeller | - | - | - | ||
Replace spark plugs | - | - | - | - | |
Inspect and replace zinc anodes | - | - | - | ||
Inspect steering and control cables | - | - | - | ||
Check exhaust system and bellows | - | - | - | ||
Full fluid changes (oil, gear oil, coolant) | - | - | - | - | |
Fog engine cylinders | - | - | - | - | |
Add fuel stabilizer and run through system | - | - | - | - | |
Flush cooling system | - | - | - | - | |
Remove battery and store with maintainer | - | - | - | - | |
Shrink wrap or cover for storage | - | - | - | - |
Track Your Boat Maintenance
Set hour-based reminders for oil changes, impeller service, and winterization. Free on iOS and Android.
Engine Service
Whether you run an outboard, sterndrive, or inboard, the engine is the heart of your boat. Regular oil changes, cooling system care, and ignition maintenance keep you running reliably on the water.
Log Every Engine Service
Build a complete marine service history. Essential for resale and insurance.
Lower Unit & Drivetrain
The lower unit transfers power from the engine to the propeller and contains critical gear oil, seals, and bearings. Neglecting it leads to expensive failures.
Fuel System
Marine fuel systems face unique challenges: ethanol-blended fuel, water contamination, and long storage periods. Proper fuel care prevents the most common boat breakdowns.
Hull & Trailer
The hull keeps you afloat and the trailer gets you to the water. Both deserve regular attention to stay safe and functional.
Winterization & Storage
Proper winterization prevents freeze damage, corrosion, and fuel degradation during the off-season. Cutting corners here leads to expensive spring surprises.
Fluid Service
- Change engine oil and filter. Acids in used oil corrode bearings over winter
- Change lower unit gear oil. Check for water intrusion before storage
- Flush cooling system with fresh water
- Add non-toxic antifreeze to inboard cooling systems
- Top up trim/tilt fluid
Fuel System
- Fill tank to 90% to reduce condensation space
- Add fuel stabilizer and run engine 10-15 minutes to circulate
- Replace fuel filter / water separator
- For carbureted engines: drain carb bowls after stabilizer circulates
- Turn off fuel valve (if equipped)
Engine Protection
- Fog engine cylinders with fogging oil through carb or spark plug holes
- Spray corrosion inhibitor on powerhead and electrical connections
- Remove spark plugs, fog cylinders, reinstall plugs
- Grease all fittings and pivot points
- Leave engine in down position (outboard) to drain water
Electrical & Battery
- Disconnect battery cables (negative first)
- Clean terminals with baking soda and water
- Charge battery fully before storage
- Connect to a smart trickle charger / battery maintainer
- Store battery in a cool, dry location off concrete
Hull & Interior
- Wash hull and deck thoroughly. Salt, dirt, and grime cause staining
- Apply marine wax to gelcoat for UV protection
- Remove all gear, coolers, and organic material (prevents mold)
- Open all hatches and compartments for ventilation
- Install a quality cover or shrink wrap. Ensure ventilation
Spring Recommissioning
- Inspect all fluid levels before first launch
- Reinstall battery and check voltage (12.6V+)
- Install drain plug. Check twice
- Test bilge pump operation
- Run engine on muffs and check for leaks, overheating, and telltale flow
- Verify all safety equipment is current and on board
Go Deeper
Track all your service intervals in one place. LookOver handles hours, miles, and dates so you never miss a service. Download free on iOS and Android.
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