Built for Marine

Designing a V-6 block solely for marine use allows Mercury to build the 4.5L with the ultimate protection system, using cast-iron componentry where the engine intersects with seawater, and using corrosion-resistant aluminum and composites everywhere else. 

 

 

 

Powerful Performer

Thanks to its new, long-runner scroll intake manifold which draws in more air and converts it into additional torque, the 4.5L delivers a ground-breaking power-to-weight ratio and gives you V-8 power in a V-6 package.

 

 

 

Smooth & Quiet

The 4.5L’s newly designed rear-facing throttle body, anti-whistle throttle plate, engine cover and mounts, lightweight flywheel, fuel-supply module, and structural oil pan all work together to deliver a superior idle, smoothness and low vibration. Resulting in an exceptional driving experience.

 

 

 

Corrosion Protection

The MercFusion Paint System creates an outer seal against the elements, while MerCathode® provides automatic protection against galvanic corrosion. For maximum defense against saltwater effects, the SeaCore® industrial hardcoat anodizing system and closed-cooling circuit is available.

 

 

 

Sporty Handling

The 4.5L comes standard with Adaptive Speed Control, which automatically maintains engine rpm regardless of load or water conditions. The result is increased throttle response and a sporty feel.

 

 

 

Easy to Maintain

When service is required, maintenance is a snap with the front-mounted drive lube monitor, color-coded maintenance points – including easy-to-reach oil filter and fill – and “how-to” videos that can be accessed via the QR code on the label.

 

 

 

• Mercruiser_4-5lt_ALPHA_Technical_Drawing.pdf
• Mercruiser_4-5lt_ALPHA_Technical_Drawing.pdf

Specifications

 

HP / kW	250 / 186
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