How to Change Outboard Oil in a Mercury Outboard
Proper maintenance of your Mercury outboard motor ensures efficient performance and reliability when you’re out on the water. One critical aspect of this maintenance is changing the engine oil. Mercury Marine recommends changing your oil every 100 or 300 hours, or more frequently if needed based on usage and conditions.
Why Oil Changes Are Crucial
Regular oil changes are the single most important thing you can do to protect your Mercury outboard. Old or contaminated oil breaks down the lubrication your gears and bearings depend on — leading to reduced performance, premature wear, and eventually costly lower unit failure.
A lower unit replacement can run $1,000 to $3,000 or more. A routine oil change costs a fraction of that. Smart boaters don’t skip this one.
Already dealing with lower unit problems? We carry remanufactured Mercury lower units — built with OEM parts by our factory-trained technicians. Most orders ship same day.
Essential Tools and Supplies
Before you begin, make sure to gather the following items:
- Socket Wrench
- Drain Pan
- Oil Filter Socket
- Oil Filter
- Funnel
- Mercury 4-Stroke Oil
- Rags
For the best results, always use genuine OEM oil and oil filters from Mercury Marine. Avoid aftermarket oil and filters, which may use substandard materials and potentially harm your engine.
Step-by-Step Instructions
Preparation
- Ensure you have all the required tools and supplies on hand.
- Watch the video tutorial above for a detailed walkthrough.
Drain the Oil
- Position a drain pan correctly beneath the oil drain plug.
- Tilt the motor as needed to allow all the oil to flow out completely.
- Once drained, securely replace the oil drain plug.
Replace the Oil Filter
- Remove the old oil filter using an oil filter socket.
- Install the new filter, ensuring it’s tightened securely.
Refill with Fresh Oil
- Use a funnel to refill the motor with Mercury 4-Stroke Oil.
- Consult your outboard owner’s manual to determine the correct amount of oil for your specific engine.
Final Steps
- Check for any oil leaks after filling.
- Run the engine briefly to ensure smooth operation.
- Recheck the oil level and top off if necessary.
Video Demonstration of How to change oil for a Mercury Outboard
Here’s the comprehensive guide to change oil for Mercury outboards of different HPs.
15-20 Hp Outboard Oil Change
APPLICABLE ENGINES:
FourStroke: I-2 333cc 15hp and 20hp
ProKicker: I-2 333cc 15hp
40-60 Hp Outboard Oil Change
APPLICABLE ENGINES:
FourStroke: I-3 747cc 40hp; I-4 995cc 40hp CT, 50hp, 50hp CT, 60hp, 60hp
75-300 Hp Outboard Oil Change
APPLICABLE ENGINES:
Verado: V-8 4.6L 250hp AMS and 300hp AMS
FourStroke: I-4 2.1L 75hp, 90hp, 90hp CT, 115hp and 115hp CT; I-4 3.0L 150hp; V-8 4.6L 250hp and 300hp; V-6 3.4L 175hp, 200hp and 225hp
Pro XS: I-4 2.1L 115hp and 115hp CT; I-4 3.0L 150hp; V-8 4.6L 200hp, 225hp, 250hp and 300hp; V-6 3.4L 175hp
SeaPro: I-4 2.1L 75hp CT, 90hp CT and 115hp CT; I-4 3.0L 150hp; V-8 4.6L 225hp, 250hp, 300hp and 300hp AMS; V-6 3.4L 200hp
