Mercury 4-Stroke Synthetic Blend Marine Engine Oil β 25W-40, 1L | 8M0078641
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Mercury 4-Stroke Synthetic Blend Marine Engine Oil β SAE 25W-40, 1L
Protect your Mercury 4-stroke engine with this genuine OEM SAE 25W-40 synthetic blend marine engine oil. Its marine-specific additive package provides corrosion protection, viscosity retention and shear resistance. Use where the engine manufacturer specifies SAE 25W-40 marine oil.
Part Details
- Part Number: 8M0078641
- Mercury Reference: 92-8M0078641
- Brand: Mercury Marine
- Product Type: 4-Stroke Marine Engine Oil β Synthetic Blend
- Viscosity: SAE 25W-40
- Container Size: 1 Litre
- Certification: NMMA FC-W and FC-W Catalyst Compatible
- Condition: New OEM
Compatible Applications
- Mercury FourStroke outboards β 2.5 HP through 400 HP
- Mercury Pro XS FourStroke outboards
- Mercury Verado FourStroke outboards
- MerCruiser 3.0L, 4.3L V6, 5.0L V8, 5.7L V8, 6.2L V8, 7.4L V8, 8.2L V8 sterndrives and inboards
- Any 4-stroke marine engine where SAE 25W-40 synthetic blend is specified β always confirm in your owner's manual
Key Features
- Synthetic blend formula β formulated for four-stroke marine engine lubrication
- FC-W and FC-W Catalyst Compatible certified β safe for catalyst-equipped engines
- Advanced marine corrosion protection β enhanced inhibitors for saltwater and humid environments
- Shear stability β maintains viscosity under sustained high-RPM and heavy-load operation
Service Interval
Change engine oil and filter at the interval specified in your engine owner's manual β typically every 100 hours or annually, whichever comes first. Always follow Mercury's published guidance for your specific model and serial number range.
Technical FAQ
- What's the difference between 8M0078641 and 8M0078639? Both are SAE 25W-40 Mercury marine oils. 8M0078641 is the synthetic blend formula. Select oil according to your engine ownerβs manual.
- What's the difference between 8M0078641 and 8M0078642? Same synthetic blend oil β 8M0078641 is the 1L bottle; 8M0078642 is the 4L jug.
- Can I use automotive synthetic oil instead? No. Automotive oils lack the marine-specific corrosion inhibitors required for boat engines and can void your warranty.
- Is this FC-W Catalyst Compatible? Yes β safe for engines equipped with catalytic converters.
- What if my engine specifies 10W-30? Use the viscosity in your owner's manual. See the Mercury 10W-30 Engine Oil β 1L (8M0078637) for that grade.
Also Available
- Mercury 4-Stroke Synthetic Blend Oil β 4L (8M0078642)
- Mercury 4-Stroke Marine Engine Oil β 1L (8M0078639)
- Mercury 4-Stroke Marine Engine Oil β 4L (8M0078640)
- Mercury 25W-50 High Performance Oil β 1 Qt (8M0078013)
- Mercury 10W-30 Engine Oil β 1L (8M0078637)
- Mercury 10W-30 Engine Oil β 4L (8M0078638)
Parts Desk Insights
8M0078641 is SAE 25W-40 synthetic blend marine engine oil. Match the oil grade and specification to your engine ownerβs manual and follow the specified service interval. The 1L bottle is convenient for top-ups; check the required fill quantity before choosing between it and the 4L jug (8M0078642).
Shipping information
In-stock and OEM parts: ship same or next business day.
Locally warehoused items: ship within 1-3 business days.
Special-order items: timeline confirmed after order.
Returns & warranty
Returns & Satisfaction Guarantee
We stand firmly behind the quality of every product we sell. Your confidence matters to us β and we back it with a straightforward 30-Day Satisfaction Guarantee.
If you are not fully satisfied, you may request a return within 30 days of delivery. All returns must receive pre-approval prior to being sent back. Unauthorized returns will not be accepted.
To qualify for a return:
Item must be in new, unused condition
Product must be in its original packaging
All parts, components, hardware, manuals, and accessories must be included
Packaging must be undamaged and suitable for resale
Important:
Electronics are strictly inspected. No returns on open-box electronics. Exceptions may apply only with prior written approval. Any electronic unit that has been installed, powered, activated, or altered may not be eligible for return.
We are serious about product integrity β and equally serious about taking care of our customers. If there is ever a product issue, contact us immediately so we can make it right.
For return authorization, please contact our support team before shipping anything back.