Uploaded May 2018 | Updated September 2026, 14 hours ago
Mercury Racing unleashes all-new 4.6L V-8 FourStroke 300R and 250R outboards.
Designed, developed and manufactured in-house, the naturally aspirated, 4.6L V-8 four-stroke engines share Mercury Racing’s venerable Quad Cam Four Valve (QC4) sterndrive DNA – complete with aluminum four-valve cylinder heads and dual overhead camshaft (DOHC) valve train. The four valve heads and DOHC valve train is integrated with Mercury’s proprietary V-8 cylinder block, packed with high performance hardware. The new platform replaces the two-stroke V-6 250XS and 300XS models.
No Replacement for Displacement
The stout V-8 powerhead provides an astounding 44% in increased displacement compared to the legacy two-strokes. That, combined with four valves per cylinder and the DOHC valve train, enables the new four-strokes to generate unprecedented torque and unmatched acceleration from the lower end of the power band up to maximum engine speed. All of this on 87-octane (90 RON) pump fuel while maintaining a comparable weight as their legacy two-stroke cousins. The weight savings can be attributed to the state-of-the-art powerhead components including composite intake runners. Both models are backed by a three-year factory warranty.
Mercury Racing unleashes all-new 4.6L V-8 FourStroke 300R and 250R outboards.
Designed, developed and manufactured in-house, the naturally aspirated, 4.6L V-8 four-stroke engines share Mercury Racing’s venerable Quad Cam Four Valve (QC4) sterndrive DNA – complete with aluminum four-valve cylinder heads and dual overhead camshaft (DOHC) valve train. The four valve heads and DOHC valve train is integrated with Mercury’s proprietary V-8 cylinder block, packed with high performance hardware. The new platform replaces the two-stroke V-6 250XS and 300XS models.
No Replacement for Displacement
The stout V-8 powerhead provides an astounding 44% in increased displacement compared to the legacy two-strokes. That, combined with four valves per cylinder and the DOHC valve train, enables the new four-strokes to generate unprecedented torque and unmatched acceleration from the lower end of the power band up to maximum engine speed. All of this on 87-octane (90 RON) pump fuel while maintaining a comparable weight as their legacy two-stroke cousins. The weight savings can be attributed to the state-of-the-art powerhead components including composite intake runners. Both models are backed by a three-year factory warranty.
