Mercury – Quicksilver 25W-40 4-Stroke Marine Engine Oil | Marine Engine Oil | Standard Finish | 8M0078620

Overview

Every boater knows that a smooth-running engine changes the whole feel of a day on the water. There’s a calm that settles in when you turn the key and hear that steady, confident hum you’ve come to trust. Quicksilver 25W-40 4-Stroke Marine Engine Oil, part number 8M0078620, is one of those behind-the-scenes essentials that helps make that moment possible. It brings the kind of protection that lets you push off from the dock without second-guessing what’s happening inside your engine, whether you are chasing a quiet sunrise or heading out for a long run offshore.

Key Features

• Designed specifically for four-stroke marine engines

• Formulated for strong corrosion resistance and dependable wear protection

• Special viscosity modifiers support high-rpm performance in modern outboards

• Twenty-five weight forty viscosity rating

• One gallon bottle size

• Mercury Marine part number 8M0078620

Engine & Boat Compatibility

• Suitable for Mercury outboards across a broad range of horsepower classes

• Works effectively in Mercury sterndrive and inboard systems requiring 25W-40 oil

• Compatible with many other leading marine engine brands using four-stroke lubrication

• Ideal for pontoons, bass boats, center consoles, cruisers, and family runabouts

Performance & Practical Benefits

Out on the water, you feel the difference good oil makes long before you think about it. The engine stays smooth during long idle stretches and steady when you push up through the throttle. This Quicksilver formula is designed to hold its viscosity even when temperatures climb or the load gets heavy, keeping the internal surfaces protected and running clean. That means tighter control, fewer surprises, and a stronger sense of trust in your equipment.

The corrosion protection is something seasoned boaters appreciate most. Salt, moisture, and constant temperature swings can take a toll on any engine, but this oil creates a durable protective layer that slows that wear down. Over time, that translates to easier maintenance, healthier components, and a quieter mind when you are miles from the dock. Even high-rpm engines benefit from its stability, giving you smooth acceleration and a confident response when you need it.

Why Buy OEM

Choosing a genuine Mercury Marine part is more than sticking with a familiar brand — it is choosing something that was engineered for the exact demands your engine faces. OEM oil is tested under the same extreme conditions as the engines themselves, so it delivers long-term reliability and consistent performance. Aftermarket blends often drift in quality, but Mercury oils are designed to protect, last, and fit the needs of your equipment the first time. It is a practical choice that saves money and stress in the long run, especially when you are committed to keeping your boat running at its best.

FAQ

Q1: Which Mercury engines does Quicksilver 25W-40 4-Stroke Marine Engine Oil fit?
It is suitable for most Mercury four-stroke outboard, sterndrive, and inboard engines calling for a 25W-40 oil.

Q2: What makes this oil different from aftermarket alternatives?
It offers stronger corrosion resistance, better wear protection, and more stable viscosity under load because it is engineered specifically for marine conditions.

Q3: How do I know if this is the correct replacement?
Check your engine manual. If it lists twenty-five weight forty for four-stroke lubrication, this is the right match.

Q4: Can this oil be used in both saltwater and freshwater applications?
Yes, it performs reliably in either environment thanks to its corrosion-resistant formulation.

Q5: Is installation straightforward?
Absolutely. If you are comfortable performing your own oil changes, you will find this oil easy to work with and consistent to pour.