Mercury 20 HP Oil & Filter Change

Tools Needed

• Socket wrench or oil filter wrench
• Oil container for draining old oil
• Funnel (not explicitly mentioned but helpful for adding new oil)
• Rag or towel to catch spills

Safety

• Wear appropriate clothing and safety glasses when working on the engine.
• Ensure the outboard is secure and stable before starting any work.

Steps

1. Lock the outboard in the full-tilt up position.
2. Position the outboard so the drain hole faces downward.
3. Remove the drain plug and drain the engine oil into an appropriate container.
4. Do not use a crankcase oil pump when changing the oil to avoid engine damage.
5. Temporarily install the drain plug, then disengage the tilt lock and lower the outboard.
6. Wait a minute for remaining oil to return to the drain.
7. Return the outboard to the full-tilt position and drain any remaining oil.
8. Inspect the drain plug seal and replace if damaged.
9. Lubricate the seal on the drain plug with oil and reinstall it.
10. Place a rag or towel below the oil filter to absorb any spilled oil.
11. Unscrew the old filter by turning it to the left.
12. Clean the mounting base of the old filter.
13. Apply a small layer of clean oil to the new filter's gasket, not grease.
14. Screw the new filter on until the gasket contacts the base, then tighten 3/4 to one turn.
15. Remove the oil fill cap and add the recommended oil to the midpoint of the oil level operating range (approximately one liter or 1.1 quarts for an empty crankcase).
16. Let the engine idle for five minutes and check for leaks.
17. Stop the engine and check the oil level on the dipstick.
18. Add oil if necessary.

Tips

• Allowing the outboard to sit with the drain plug removed for a minute helps ensure all old oil is drained.
• Using grease on the filter gasket can attract dirt and debris, so only use clean oil.