Sierra 9420CAT2 4-Stroke Mineral Marine Outboard Engine Oil, 10W-30, 1 Quart
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Sierra 9420CAT2 4-Stroke Mineral Marine Engine Oil, 10W-30 – 1 Quart
A premium mineral-base 10W-30 engine oil formulated specifically for marine 4-stroke outboard engines. Sierra 9420CAT2 meets or exceeds the lubrication requirements of Mercury, Yamaha, Johnson-Evinrude, Suzuki, and Honda outboards — providing reliable protection against wear, corrosion, and sludge buildup in a convenient single-quart size.
At 1 quart (946 mL), this is the right size for smaller outboards, top-ups between full services, or trying the oil before committing to a larger quantity.
Key Features
- Marine-specific formulation — engineered for the demands of 4-stroke outboard engines, not repurposed automotive oil
- Anti-wear additives — reduce friction and protect engine internals under sustained load
- Maximum corrosion protection — guards against moisture and salt exposure in the marine environment
- Sludge control — keeps engine internals cleaner for better long-term efficiency
- Low-temperature viscosity — supports reliable cold-weather and cold-start performance
- Broad OEM compatibility — meets API SJ, CF-2, and CH-4 service classifications
Specifications
- Viscosity: SAE 10W-30
- Base stock: Mineral
- API service: SJ, CF-2, CH-4
- Volume: 1 US quart (946 mL)
- Part number: 9420CAT2 | SKU: 47-9420CAT2
- Compatible engines: Mercury, Yamaha, Johnson-Evinrude, Suzuki, Honda 4-stroke outboards
Best Use Case
The 1-quart size is ideal for small outboards (under 50 HP) where a full drain-and-fill requires less than a litre, or for topping up oil between scheduled services on larger engines. It’s also a practical choice for boaters who want to try the oil before purchasing in larger quantities.
For a full service on mid-size outboards, the Sierra 9420CAT3 10W-30, 1-Gallon offers better value per litre. For high-volume shop use, see the Sierra 9420CAT7 10W-30, 55-Gallon Drum. For a synthetic blend upgrade with FC-W certification, see the Sierra 9421CAT2 Synthetic Blend 10W-30, 1 Quart.
Parts Desk Insights
Best use case is the small-engine recreational boater — portable outboards, tenders, and small fishing boats under 50 HP where a quart is all that’s needed for a full service. Also a strong seller as a top-up product for customers who already have a larger engine and just need to bring the oil level up between changes. Upsell path: customers doing a full service on a mid-size or larger outboard should be directed to the 1-gallon (9420CAT3) for better value. For warranty-conscious Yamaha and Mercury customers, flag the FC-W certification question and redirect to the Sierra 9421CAT2 Synthetic Blend (FC-W) if needed. Always confirm OEM oil spec in the owner’s manual before recommending.
Shipping information
In-stock and OEM parts: ship same or next business day.
Locally warehoused items: ship within 3–4 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 — 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 — 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.