Each engine type has unique maintenance requirements. Understanding these differences helps you care for your specific setup.
Outboard Engine Maintenance
Self-contained units mounted on the transom—popular for simplicity.
| Task | Frequency | DIY Difficulty |
|---|---|---|
| Oil change | 100 hours/annually | Easy |
| Lower unit oil | 100 hours/annually | Easy |
| Spark plugs | 100-300 hours | Easy |
| Water pump impeller | 2-3 years | Moderate |
| Anodes | Annually | Easy |
💡 Outboard Tip
Always flush with fresh water after saltwater use—at least 10 minutes. This dramatically extends engine life.
Inboard Engine Maintenance
Mounted inside the hull, connected to shaft and propeller.
| Task | Frequency | DIY Difficulty |
|---|---|---|
| Oil and filter | 100 hours/annually | Moderate |
| Transmission fluid | 100-200 hours | Moderate |
| Raw water impeller | 2-3 years | Moderate-Difficult |
| Shaft seal/packing | Inspect annually | Difficult |
| Cutlass bearing | 3-5 years | Professional |
Stern Drive Maintenance
Combines inboard engine with outboard-style lower unit—requires attention to both.
⚠️ Critical: Stern Drive Bellows
Bellows are critical waterproof seals. If they fail, your boat can sink. Inspect annually, replace every 5-7 years. Professional service recommended.
Annual Cost Comparison
| Type | DIY Cost | Professional |
|---|---|---|
| Outboard | $100-200 | $300-500 |
| Inboard Gas | $150-300 | $400-700 |
| Stern Drive | $200-350 | $500-800 |
For detailed budgeting, see How to Budget for Annual Maintenance.
Find qualified marine mechanics for your engine type through Boatwork.
