Yanmar YSM12 Marine Inboard Diesel Engine 12hp

Description

Yanmar YSM12 Marine Inboard Diesel Engine 12HP

The Yanmar YSM12 12HP marine inboard diesel engine is a single-cylinder, horizontal four-stroke diesel with a displacement of 0.510 litres. Yanmar’s original documentation lists 12HP at 3,000 rpm as a one-hour rating and 10HP at 3,000 rpm for continuous operation. nhmr.nl

For owners seeking a Yanmar YSM12 12HP engine for sale, MSS Motorsports UG welcomes enquiries for replacement-engine pricing, available equipment and delivery quotations. Provide the complete engine designation and existing drivetrain details to establish the required package.

Horizontal Diesel Propulsion for Replacement Projects

The Yanmar YSM12 12HP uses a precombustion-chamber combustion system and a seawater-cooling arrangement. Its horizontal cylinder layout is an important consideration when assessing installation space, engine mounts and shaft alignment.

For a sailboat or small displacement vessel, consider the engine where the power requirement, operating profile and installation suit its specifications.

Key features include:

• Single-cylinder construction: A horizontal, four-stroke marine diesel layout.
• 510 cc displacement: An 85 × 90 mm bore and stroke.
• Precombustion-chamber combustion: An indirect-injection arrangement.
• Original seawater cooling: Forced circulation through a rubber-impeller pump.
• Mechanical marine transmission: A reduction and reversing arrangement with a wet single-disc clutch. Manualzz

Technical Specifications

These are reference specifications from Yanmar’s original YSM operation and workshop manuals. Confirm the model suffix, fitted equipment and any modifications for the particular engine offered. Manualzz

Understand the 12HP Rating

The 12HP designation is the one-hour rating. Use the separately published 10HP continuous rating when discussing sustained operation and propulsion requirements with your installer. nhmr.nl

The engine’s suitability also depends on the vessel’s displacement, hull form, propeller and gearbox ratio. Matching the advertised horsepower alone does not establish installation compatibility.

Review the Yanmar YSM operation manual, preserved in a marine technical archive, for original manufacturer information.

Gearbox, Controls and Cooling Configuration

The original YSM documentation describes a mechanical reduction and reversing transmission with a wet single-disc clutch. Confirm the fitted gearbox ratio, output coupling, shaft arrangement and control connections before ordering.

Starting equipment varies between versions. The quotation should identify whether the engine includes an electric starter, alternator, manual-start components, instruments and wiring. nhmr.nl

For an engine retaining its original seawater-cooling system, request information on the cooling passages, pump, hoses, exhaust components and available inspection records. Ask for running-test evidence showing cooling-water discharge and operation at the stated test conditions.

For a different output within the same family, compare the Yanmar YSM8 marine inboard diesel engine. Check installation and propulsion requirements separately for each model.

Confirm the Condition and Supply Scope

When comparing a Yanmar YSM12 12HP price, request a written quotation confirming:

• Engine condition, identification details and operating hours where documented.
• Available service history, repair or rebuild records and inspection findings.
• Cold-start and warm-running evidence, where available.
• Gearbox condition, reduction ratio, coupling and included controls.
• Starter, alternator, instruments, wiring, mounts and exhaust equipment supplied.
• Any warranty offered, including the provider, coverage and exclusions.
• Availability, packing, dispatch estimate and delivery charges.

For a replacement enquiry, provide photographs of the existing engine and gearbox identification plates. Include measurements of the mounting arrangement, shaft position and available machinery space so your installer can assess the proposed engine.

Frequently Asked Questions

Is the Yanmar YSM12 12HP rated at 12HP continuously?

No. Yanmar’s original documentation lists 12HP as a one-hour rating and 10HP as the continuous rating, both at 3,000 rpm. nhmr.nl

Is the original YSM12 freshwater cooled?

The workshop manual specifies direct seawater cooling. Confirm the actual arrangement if the engine has been modified. Manualzz

Does the engine include a gearbox and manufacturer warranty?

Inclusions and warranty depend on the particular unit and supply arrangement. Request an itemised quotation and written terms for any warranty offered.

Request Your Yanmar YSM12 Quote

Contact MSS Motorsports UG for a Yanmar YSM12 quotation with your vessel make and model, complete engine designation, gearbox model and ratio, intended operating profile and purchase timing. Include your billing and delivery addresses to request equipment pricing and transport costs for your destination.