Yanmar 3JH40 – Marine Diesel Engine 40 HP

With 40 hp at 3,000 rpm, the Yanmar 3JH40 combines a naturally aspirated 1.642L inline three-cylinder configuration with common rail injection. The stated 17.0:1 compression ratio and EN 590 diesel requirement define its fuel-system setup. Mechanical or saildrive transmission options, KM35A2, KM35P, or SD60 drive compatibility, and electronic-control support shape the documented propulsion integration choices.

The 423-pound dry engine uses an SAE 4 flywheel housing and a 12V 125-amp alternator. Enclosed forced lubrication holds 5.0L oil, while heat-exchanger cooling uses 4.5L coolant and the wet mixing elbow forms part of the exhaust system. Listed emissions ratings include EPA Tier 3, RCD II, and BSO II.

Why Choose the Yanmar 3JH40 Marine Diesel Engine

The 3JH40 marine diesel engine combines 40 hp at 3,000 rpm with common rail injection in a naturally aspirated 1.642L three-cylinder layout. Buyers comparing propulsion packages can assess its 12V 125-amp alternator, electronic-control compatibility, mechanical or saildrive options, and KM35A2, KM35P, or SD60 drive configurations. Its 423-pound dry weight and EPA Tier 3 rating provide additional integration context.

Warranty and Support

This model is eligible for Yanmar’s 3-Year Extended Limited Warranty program for first retail purchasers, subject to private and recreational use requirements. provides product-information support before purchase and assistance with order-related questions. Review warranty eligibility and current coverage details on before placing your order.

Before Ordering the Yanmar 3JH40 Marine Diesel Engine

Before ordering, verify engine-bed dimensions, mount locations, SAE 4 flywheel-housing compatibility, selected transmission type, and the required KM35A2, KM35P, or SD60 drive arrangement. Confirm the vessel has EN 590 diesel fuel supply, cooling-water and wet-exhaust systems, compatible electronic controls, 12V wiring, ventilation, shaft or saildrive alignment, and professional installation planning.