Mercury 250 HP ECT 4.5L Inboard Engine

The  Mercury 250 HP ECT 4.5L Inboard Engine features a V-6 block designed exclusively for marine use, incorporating an innovative protection system. Key components are made of cast-iron where the engine interacts with seawater, while corrosion-resistant aluminum and composites are used throughout the rest of the engine for durability and reliability.

Repower Financing

With Mercury Repower Financing, powering up your boat is easier than ever. Whether it’s a fishing boat, runabout, or cruiser, Mercury offers flexible financing on the engine, along with options to finance rigging, gauges, controls, and even labor. Get low rates and affordable monthly payments that fit your budget.

Owner’s Manuals

Need an Owner’s Manual for your Mercury engine? It’s easy to access! You can purchase a printed copy or download and print your own from Mercury’s official website. The manuals offer guidance for maintenance, part replacements, and more.

Powerful Performer

Equipped with a long-runner scroll intake manifold, the 4.5L engine improves airflow, generating additional torque for a better power-to-weight ratio. This allows you to experience V-8 power in a V-6 engine, delivering exceptional performance and efficiency.

Smooth & Quiet

The Mercury 250 HP engine features a newly designed rear-facing throttle body, anti-whistle throttle plate, optimized engine cover, lightweight flywheel, and structural oil pan, all working together to deliver a smooth, quiet ride with minimal vibration. This results in a refined and exceptional driving experience.

Corrosion Protection

Mercury’s MercFusion Paint System creates an outer seal that shields the engine from the elements. MerCathode® technology provides automatic protection against galvanic corrosion, while the SeaCore® industrial hardcoat anodizing system and closed-cooling circuit offer additional protection against saltwater damage.

Sporty Handling

The 4.5L engine comes equipped with Adaptive Speed Control, which ensures consistent engine rpm regardless of load or water conditions. This results in better throttle response and a sportier, more intuitive driving experience.

Easy to Maintain

Maintaining your Mercury 250 HP engine is simple with front-mounted service points, color-coded maintenance indicators, and easy access to the oil filter and fill. Mercury even provides “how-to” videos accessible via the QR code on the engine label for straightforward servicing.

 Mercury 250 HP ECT 4.5L Inboard Engine SPECS:

• HP / kW: 250 / 184

• Maximum RPM (WOT): 4800-5200

• Engine Type: V6, 2-valve/cylinder pushrod

• Displacement (L): 4.5

• Displacement (CID/L): 275 / 4.5

• Bore and Stroke: 4.0 x 3.6″ / 102 x 92 mm

• Recommended Fuel: Unleaded Regular 87 Octane Minimum (R M/2) or 90 RON 10% Ethanol Maximum

• Fuel Ethanol Tolerance: Up to 10%

• Fuel Requirement: 90 RON 10% Ethanol Maximum, Unleaded Regular 87 Octane Minimum (R M/2)

• Engine Control System: Mechanical Shifting with Optional SmartCraft DTS, Standard SmartCraft with Electronic Throttle Control

• Fuel Delivery System: Computer-controlled Multi-Port Electronic Fuel Injection (MPI)

• Air Induction: Performance-Tuned Scroll Intake Manifold

• Ignition: SmartCraft PCM 112 Digital Inductive

• Alternator Amp / Watt: 70 amp / 882 watt (Belt-Driven)

• Water Drain System: Air Actuated “Season Extender” (Bravo), Easy Drain “Season Extender” (Alpha)

• Exhaust System: Through prop

• Cooling System: Water-cooled with thermostat; FWC available as factory option (Alpha) and packaged with SeaCore Drive (Bravo)

• Lubrication System: Integrated wet sump

• Recommended Oil: NMMA Certified FCW 25W-40 Synthetic Blend

• Engine Guardian System: SmartCraft Engine Guardian

• Dimensions (L x W x H): 28 x 30 x 22″ / 696 x 740 x 559 mm

• Weight (Engine Only): 761 lbs / 345 kg

• Compatible Drives: Alpha, Bravo One, Bravo Three, Bravo Two

Availability: 10 In Stock
Model: Mercury 250 HP ECT
Brand: Mercury