Mercury 300 HP SeaPro Electric Start, Steering, Power Trim and Tilt, Ultra Long Shaft Outboard Engine

The Mercury S 300 XXL SeaPro is a 4-stroke outboard marine engine designed for commercial fishing boats, rental tour boats, water taxis, and high-usage vessels requiring an extra-long shaft. It boasts 300 HP / 224 kW and a 4600 cc V8 (8-cylinder) engine. The SeaPro series is Mercury's specially developed line of outboards for commercial and heavy-duty applications. Enhanced durability, Smart Craft integration, and extended service intervals are optimized for the needs of commercial operators.

S 300 XXL SeaPro Series Features and Technology Advantages

SeaPro engines aim for long life in saltwater environments with a reinforced cooling system and increased anode protection compared to standard FourStroke series. The Smart Craft gauge system allows for fleet-specific engine monitoring.

• V8 (8-Cylinder) Engine (4600 cc): SeaPro engines aim for long life in saltwater environments with a reinforced cooling system and increased anode protection compared to standard FourStroke series
• Extra Long Shaft (635 mm (25")): The propeller operates at an optimal depth with the correct transom height
• SeaPro Durability Package: Reinforced cooling, increased anode protection, and extended service intervals
• Electric Start: Instant activation with a key or button — comfortable and quick starting
• Electric Trim & Tilt (Power Trim & Tilt): Adjust trim angle with a button while cruising — fuel efficiency optimization; full motor tilt for raising
• External Fuel System with Float: Large capacity external tank connection — range determined by user needs

Extra Long Shaft — What Boat Type Is It Suitable For?

The extra-long shaft (635 mm (25")) keeps the propeller at an optimal depth on large yachts and professional boats with deep transom designs. Incorrect shaft selection will leave the propeller out of the water or scrape the bottom — measure your transom height before installation.

Technical Specifications

Who Is This Engine For?

• Commercial fishing and tour boats: SeaPro's increased durability for intensive daily use
• Water taxis and rental boats: low maintenance costs and extended service intervals
• Search and rescue and patrol boats: reliable power and Smart Craft engine monitoring
• Coastal fishing fleet-specific: comparative performance and durability with standards

Maintenance and Longevity

4-stroke Mercury engines operate trouble-free for many years with regular oil changes and end-of-season maintenance protocols. The impeller of the water-cooled system should be checked every 100 hours or every two seasons. In saltwater use, freshwater flushing is mandatory after every use.

Related maintenance categories: Maintenance Kit | Engine Oil | Impeller | Mercury Spare Parts

Frequently Asked Questions

Why is the Mercury SeaPro 300 HP recommended for commercial use?

The SeaPro series offers a reinforced cooling system and increased anode protection compared to standard FourStroke engines. Smart Craft integration facilitates fleet management and engine monitoring. Extended service intervals reduce operational costs.

What does the Smart Craft system provide in SeaPro engines?

Smart Craft transmits engine status, fuel consumption, temperature, and hourly operating data to a digital display. In multi-engine configurations, each engine can be monitored separately. The early fault warning system prevents unexpected breakdowns.

What are the maintenance intervals for SeaPro engines?

SeaPro engines are designed for extended service intervals. Oil changes should be performed according to manufacturer recommendations. In saltwater use, freshwater flushing after every use and end-of-season anode inspection are mandatory.

Which boat and vessel brands are compatible with the S 300 XXL SeaPro?

Mercury outboard engines are compatible with many fiberglass, aluminum, and inflatable boat models thanks to their universal transom clamp or transom mounting system. The only criteria are your boat's 635 mm (25") transom height and the maximum engine power approved by the manufacturer. You can get compatibility confirmation from Clever Marin by sharing your boat model.

Related Products and Categories

• Mercury Outboard Engines
• Mercury Marine Products
• Mercury Spare Parts
• Mercury 75–150 HP FourStroke
• Mercury SeaPro Engines
• Outboard Engines
• Boat Engines
• Maintenance Kit
• Impeller
• Anode

Is This the Right Configuration for Your Boat?

Share your boat model, transom height, and intended use — let's verify together if the Mercury S 300 XXL SeaPro engine is suitable for your boat and ensure the correct shaft selection.