When it comes to compact, reliable, and highly efficient auxiliary power for small motorboats and sailboats, the Yanmar 2YM15 stands out as an industry favorite. Designed specifically to thrive in harsh marine environments, this engine combines lightweight construction with heavy-duty performance, meeting strict EPA Tier 3 emissions standards.
Whether you are looking to repower an existing vessel or configure a new build, the Yanmar 2YM15 delivers peace of mind on the water.
Engine Specifications Overview
The 2YM15 is a naturally aspirated, 4-stroke, vertical, water-cooled diesel engine featuring Yanmar’s proven indirect injection combustion system. Below are the foundational specifications for the standard engine model:
- Configuration: In-line, 4-stroke, vertical, water-cooled diesel engine
- Number of Cylinders: 2 cylinder
- Displacement: 0.570 L (34.7 cu in)
- Bore x Stroke: 70 mm x 74 mm (2.75 in x 2.91 in)
- Maximum Output at Crankshaft: 10.0 kW @ 3600 rpm (14 mhp @ 3600 rpm)
- Continuous Power (ISO 8665): 9.1 kW @ 3489 rpm
- Aspiration: Natural
- Alternator: 12V – 125A
- Cooling System: Fresh water cooling with heat exchanger
- Direction of Rotation (Crankshaft): Counterclockwise (CCW) viewed from stern
- Dry Weight (Without Gear): 103 kg (227 lbs)
Marine Gear & Drive Options
The Yanmar 2YM15 can be configured with a traditional mechanical marine gearbox or integrated into a Saildrive system, depending on your hull configuration:
| Feature / Options | KM2P-1 Marine Gear Yanmar 2YM15 Specifications | Saildrive [SD25] Yanmar 2YM15 Specifications |
| Clutch Type | Mechanical cone clutch | Constant mesh gear with dog clutch |
| Reduction Ratios (Fwd/Asn) | 2.21 / 3.06, 2.62 / 3.06, 3.22 / 3.06 | 2.64 / 2.64 |
| Rotation (Viewed from Stern) | Clockwise | Counterclockwise |
| Total Dry Weight (Engine + Drive) | 113 kg (249 lbs) | 133 kg (293 lbs) |
Decoding Yanmar “YM” Models
In Yanmar’s marine engine lexicon, model designators provide vital structural clues regarding the block configuration:
15: Represents the nominal horsepower rating group (with this unit outputting up to 14 mhp.
Y: Denotes the engine family series, showcasing Yanmar’s purpose-built utility multi-cylinder line designed specifically for sailboats and light displacement hulls.
M: Indicates a Multi-cylinder layout, signifying smooth power delivery compared to legacy single-cylinder platforms.
Common Maintenance Parts & VETUS Cross-Reference Guide
Keeping your Yanmar 2YM15 in peak operating condition requires routine maintenance. To help you source components easily, we have compiled a quick cross-reference chart mapping essential engine requirements to high-grade VETUS system alternatives.
| Maintenance Item / System | Yanmar Factory Spec / Size | VETUS Part / Match |
| Engine Lube Oil Class | API Class CD or higher (10W-30 or 15W-40) | Standard Marine Lube |
| Water Strainer Hose Conn. | 14 mm Inlet | Type FTR330 or 470/13 |
| Water Strainer Full Kit | — | WKIT33013 |
| Exhaust Hose Diameter | 45 mm | 45 mm VETUS Exhaust Hose |
| Waterlocked Exhaust | Exhaust Pipe Ø 51 mm | NLP(3)45(HD) / LP / LSS45 |
| Combi Waterlock/Muffler | — | NLPH45 |
| Muffler Type | — | MP45 |
| Gooseneck | — | LT45 |
| Combi Muffler/Gooseneck | — | NLPG45 |
| Exhaust Transom Conn. | — | 45R/PV or SV |
| Minimum Starting Battery | 12V System | VESMF70 (Min. 70 Ah) |
| Propeller (Displacement) | 3-Blade Matching | Manganese Bronze P3B (12″ or 13″) |
| Folding Propeller (2-Blade) | Flexofold Network | Flexofold 13″ or 14″ |
| Folding Propeller (3-Blade) | Flexofold Network | Flexofold 15″ |
| Air Suction Vent | — | 1 x ASV020 |
| Part Name | Yanmar OEM Part No. | Aftermarket Cross-Reference | Recommended Service Interval |
| Engine Oil Filter | 119305-35170 (Supersedes 119305-35151) | • Wix 51365• Fram PH3593A• Sierra 18-7911-1 | Replace every 100 hours or annually |
| Secondary Fuel Filter(On-engine element) | 104500-55710 | • Wix 33262• Fram C7516• Baldwin PF937• Sierra 18-7703 | Replace every 250 hours or annually |
| Fuel Filter O-Ring | 24341-000440 | (Typically included with premium aftermarket filters) | Replace with every fuel filter change |
| Seawater Impeller Kit(Includes O-ring & pins) | 128990-42570 (Supersedes 128990-42200) | • Johnson 09-810B• Jabsco 6530-0001• Sierra 18-3081 | Inspect every 100 hours;Replace every 200 hours or annually |
| Air Intake Filter Element | 128270-12540 | • Sierra 18-57703 | Clean every 100 hours;Replace as required |
| Coolant / Water Pump V-Belt | 104511-78780 (M19) | • Premium V-Belt Size M19 | Inspect & adjust tension every 100 hours |
| Alternator V-Belt (Up to Engine Serial #E05887) | 129612-42290 | • Gates / Sierra Equivalent | Inspect & adjust tension every 100 hours |
| Alternator Serpentine Belt (Engine Serial #E05888 and after) | 128790-77580 | (For upgraded 120 Amp Valeo alternators) | Inspect & adjust tension every 100 hours |
| Thermostat (71°C) | 128990-49800 | • Recmar REC128990-49800 | Test or replace every 500 hours |
Pro-Tip on Impellers & Belts: The 2YM15 uses a pin-drive, slotted-shaft configuration for its raw-water impeller, rather than a splined layout. Always verify that your aftermarket choice specifies the pin layout before leaving the store. Additionally, checking your engine’s serial number plate before buying an alternator belt will save you an unnecessary second trip, as the transition to the flat, ribbed serpentine style completely changed the belt profile.
For repower consultations, parts ordering, or further details regarding the Yanmar YM-Series, contact the experts at Murray Yacht Sales.
Questions about a vessel with a 2GM or any variant? Our team at Murray Yacht Sales is glad to help you think through what you are looking at. Reach out anytime.
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