From the Atomic 4 to today's modern diesels, Universal Marine has led the way in auxiliary marine propulsion. The current production lineup is the B-Series — three-cylinder naturally aspirated diesels designed for clean emissions, low noise, and high low-end torque. Used by leading sailboat builders and as direct replacements for older Universal installations.

Current Production Models

M3-20B

20 HP

M-25XPB

26 HP

M3-20B

20 HP marine diesel

The smaller of the two B-Series options — a three-cylinder, naturally aspirated diesel built around the latest advancements in diesel engine design. Designed for cleaner emissions, lower noise, and higher horsepower at lower RPM than the engines it replaces.

Like the rest of the Universal B-Series, the M3-20B delivers high low-end torque and is positioned as one of the quietest and most durable marine engines currently available.

Continuous Output	20 HP
Cylinders	3
Displacement	43.80 cu. in. (0.72 L)
Bore × Stroke	2.64" × 2.68"
Aspiration	Natural
Cooling	Fresh water
Std. Transmission	Marine gear, 2.05:1 reduction (V-drive 2.13:1 optional)
Dimensions (L × W × H)	26.40" × 18.80" × 20.10"
Dry Weight	241 lbs
Manufacturer Page	View on westerbeke.com

M-25XPB

26 HP marine diesel

The larger B-Series option — same three-cylinder, naturally aspirated design language with a bigger 1-liter displacement for installations needing more power.

Cleaner emissions, reduced noise, and increased horsepower at lower RPMs are the family hallmarks. High low-end torque suits sailboat auxiliary duty.

Continuous Output	26 HP
Cylinders	3
Displacement	61.20 cu. in. (1.00 L)
Bore × Stroke	2.99" × 2.90"
Aspiration	Natural
Cooling	Fresh water
Std. Transmission	Marine gear, 2.05:1 reduction (V-drive 2.13:1 optional)
Dimensions (L × W × H)	28.40" × 18.90" × 22.10"
Dry Weight	295 lbs
Manufacturer Page	View on westerbeke.com