6.5 MCG – 6.5kW, 60 Hz low-CO Gas Generator

Description

Westerbeke 6.5 MCG 6.5 kW 60 Hz Low-CO Marine Gasoline Generator

Compact, Low-Speed Auxiliary Power with Multiport EFI

The Westerbeke 6.5 MCG 6.5 kW 60 Hz Low-CO Marine Gasoline Generator is a compact, electronically controlled generator developed for gasoline-powered motor yachts, cruisers, houseboats, passenger craft, and other compatible marine vessels.

Important correction: The Westerbeke 6.5 MCG is a gasoline or petrol generator—not a diesel generator. It uses sequential multiport electronic fuel injection, a water-cooled returnless fuel system, and Westerbeke’s Low-CO exhaust technology.

The 6.5 MCG-614 delivers 6.5 kW at 120V, 60 Hz and 1800 RPM, with a rated output of 54.1 amps. Its three-cylinder engine, electronic governing, four-pole brushless alternator, freshwater cooling, remote starting, and compact low-profile construction make it suitable for vessels requiring dependable onboard electrical power without using a high-speed 3600 RPM generator.

This generator may support compatible onboard systems such as:

• Battery chargers and inverter-chargers
• Refrigerators and freezers
• Freshwater and seawater pumps
• Lighting circuits
• Navigation and communication electronics
• Entertainment systems
• Electrical outlets
• Selected galley appliances
• Appropriately sized air-conditioning systems

Generator suitability must be confirmed through an electrical-load calculation that considers continuous demand, motor-starting current, simultaneous use, and adequate reserve capacity.

Production and Availability Status

The Westerbeke 6.5 MCG 6.5 Low-CO is no longer in production. Westerbeke continues to publish parts information, manuals, technical specifications, diagrams, and service documents for the model. Available units may therefore consist of unused old stock, surplus generators, or professionally reconditioned units.

Before purchasing an available unit, confirm:

• Serial number and production date
• New, surplus, used, or reconditioned condition
• Total operating hours
• Included control panel and wiring harness
• Catalyst condition and service history
• Fuel-system condition
• Warranty status
• Parts availability
• Compatibility with the vessel

Any advertised Westerbeke 6.5 MCG 6.5 price should therefore be assessed together with the generator’s condition, included accessories, warranty terms, and maintenance history.

Low-Profile Marine Generator Design

Westerbeke described the 6.5 MCG as one of the more compact Low-CO, low-speed gasoline generators available during its production period. Its marine configuration allowed it to provide 6.5 kW of output in dimensions comparable with some smaller high-speed generators.

The generator combines:

• Low-speed 1800 RPM operation
• Three-cylinder gasoline engine
• Sequential multiport EFI
• Water-cooled returnless fuel system
• Electronic engine governing
• Low-CO catalytic exhaust treatment
• Freshwater cooling with heat exchanger
• Brushless four-pole alternator
• Remote start-and-stop controls
• Automatic warning and shutdown functions
• Belt-driven raw-water pump
• Vibration-isolating mounts
• AC circuit-breaker protection

These features make the generator suitable for compatible original installations and marine generator replacement projects where space, noise, vibration, fuel type, and electrical output are important.

Three-Cylinder Gasoline Engine

The Westerbeke 6.5 MCG 6.5 is powered by a naturally aspirated, three-cylinder, four-stroke gasoline engine with a displacement of 40.3 cubic inches or approximately 0.66 litres. It produces approximately 11 hp at its rated 1800 RPM operating speed.

The engine uses an aluminium cylinder head, cast-iron cylinder block, forged crankshaft supported by four main bearings, and overhead rotating valves.

A balance shaft helps reduce vibration from the three-cylinder engine, while operation at 1800 RPM contributes to smoother and quieter performance compared with many 3600 RPM gasoline generator sets.

6.5 kW Electrical Output at 60 Hz

The Westerbeke 6.5 MCG-614 provides 6.5 kW of single-phase electrical power at 120V and 60 Hz.

These ratings are taken from Westerbeke’s official advanced specification sheet.

The generator platform was described as field-convertible between 50 and 60 Hz. However, a frequency conversion changes the rated speed and electrical output. Any conversion should be completed according to Westerbeke procedures by a qualified technician, with the vessel’s voltage, wiring, circuit protection, and connected appliances reviewed before use.

Multiport Electronic Fuel Injection

The 6.5 MCG 6.5 uses sequential multiport electronic fuel injection, commonly abbreviated as MPI or EFI.

Instead of using a conventional carburettor, the EFI system electronically controls fuel delivery to support:

• Easier starting
• More precise air-to-fuel control
• Improved fuel efficiency
• Reduced emissions
• Consistent response as electrical load changes
• Electronic diagnostic capability

Westerbeke states that the EFI system works with electronic speed control to maintain constant engine speed and reduce “bogging down” when electrical loads are connected.

Westerbeke also provides compatible diagnostic software for the 6.5 MCG. The manufacturer recommends that the software and related service procedures be used by qualified technicians.

Water-Cooled Returnless Fuel System

The Westerbeke 6.5 MCG 6.5 incorporates a water-cooled returnless gasoline fuel system.

High temperatures inside a vessel’s machinery space can cause gasoline to vaporise, potentially resulting in vapor lock and unstable fuel delivery. Westerbeke’s water-cooled returnless design was intended to reduce this risk and improve operation in high ambient temperatures.

The vessel’s fuel installation should include:

• Approved marine gasoline fuel hose
• Properly sized supply piping
• An accessible fuel shutoff valve
• Suitable fuel filtration
• Proper grounding and bonding
• Ignition-protected components
• Adequate machinery-space ventilation
• Secure, leak-free fittings

Gasoline fuel-system installation and servicing should only be undertaken by qualified marine technicians.

Westerbeke Low-CO Technology

The Low-CO designation does not mean zero carbon monoxide and does not make gasoline-engine exhaust safe to breathe.

Westerbeke’s system reduces normal exhaust CO levels through precise electronic control of the engine’s air-to-fuel ratio combined with exhaust after-treatment using a special catalyst. Actual CO concentration can vary according to engine load and the condition of the fuel, air, control, and catalyst systems.

Carbon monoxide is colourless, odourless, tasteless, poisonous, and potentially fatal. Westerbeke instructs operators not to rely on outdoor dilution for safety and stresses the importance of installing and maintaining a functioning marine CO detector.

A Low-CO generator still requires:

• Correct exhaust design
• Leak-free exhaust connections
• Adequate ventilation
• Working carbon-monoxide detectors
• Correct catalyst maintenance
• Regular inspection of fuel and air systems
• Proper discharge positioning away from occupied areas

If a CO alarm activates, engines and generators should be stopped, the vessel evacuated and ventilated, and professional assistance obtained.

Low-CO Catalyst Maintenance

The catalyst is essential to the Low-CO system. Water entering the exhaust can damage the catalyst and compromise emissions performance, making correct wet-exhaust design and installation particularly important.

The operator’s manual specifies that:

• Catalyst performance degrades with operating time
• CO output should be checked seasonally or every 1,000 hours, whichever comes first
• Verification requires an appropriate CO analyser
• The catalyst must be replaced every 2,000 operating hours
• The catalyst should be inspected for water-intrusion damage

These inspection and replacement intervals are especially important when assessing a used or reconditioned 6.5 MCG 6.5.

Electronic Governing for Stable Frequency

The 6.5 MCG 6.5 uses an electronic engine governor to help maintain 1800 RPM as the connected electrical load changes.

When a refrigerator compressor, pump, air-conditioning unit, or battery charger starts, the engine experiences an immediate increase in mechanical demand. The electronic governor adjusts engine operation to reduce speed loss and maintain stable frequency.

Published frequency regulation is approximately 0.5 Hz, or 1%, from no load to full load.

Stable frequency supports the reliable operation of compatible:

• Refrigeration systems
• Battery chargers
• Electric pumps
• Air-conditioning compressors
• Navigation electronics
• Communication equipment
• Lighting circuits
• Entertainment systems

Electronic governing improves load response but does not compensate for continuous overloading or incorrect generator sizing.

Brushless Four-Pole Alternator

The Westerbeke 6.5 MCG 6.5 uses a brushless, four-pole revolving-field alternator.

Its published design features include:

• Brushless construction
• Four-pole configuration
• Revolving electrical field
• Class H insulation
• Direct-connected centrifugal cooling blower
• Approximately ±5% voltage regulation
• Approximately 0.5 Hz frequency regulation

The four-pole design enables the generator to produce 60 Hz electricity at 1800 RPM. Brushless construction reduces routine maintenance associated with carbon brushes, while Class H insulation provides thermal protection for the electrical windings.

Westerbeke states that the generator’s electromagnetic-interference performance exceeds the requirements of most marine radio telephones and standard televisions. Correct grounding, cable routing, circuit protection, and vessel wiring remain necessary for reliable performance. 6.5 MCG 6.5

Freshwater Cooling with Marine Heat Exchanger

The 6.5 MCG 6.5 uses a freshwater cooling system with a marine heat exchanger.

Engine coolant circulates internally through the engine and freshwater-cooled exhaust manifold. Raw water drawn from outside the vessel removes heat through the exchanger before being injected into the wet-exhaust system.

The system includes:

• Closed freshwater coolant circuit
• Marine heat exchanger
• Freshwater-cooled exhaust manifold
• Coolant-recovery arrangement
• Belt-driven raw-water pump
• Water-injected exhaust elbow
• ¾-inch raw-water connection

The published cooling-system capacity is approximately 3.5 US quarts or 3.3 litres.

Routine maintenance should include inspection of:

• Coolant level and condition
• Raw-water strainer
• Seawater-pump impeller and belt
• Heat exchanger
• Cooling hoses and clamps
• Zinc anode
• Water-injected exhaust elbow
• Siphon break
• Waterlift muffler and exhaust hose

Westerbeke warns that a siphon break is required when the exhaust-manifold injection point is at or below the vessel’s loaded waterline. Incorrect exhaust design can allow seawater to enter the engine or catalyst.

Approximate Fuel Consumption

Westerbeke publishes the following approximate gasoline-consumption figures for the 6.5 MCG 6.5 at 1800 RPM:

These figures are approximate. Actual fuel use will depend on electrical demand, engine condition, fuel quality, installation, machinery-space temperature, ventilation, and maintenance.

One-Touch Starting and Safety Protection

The original generator package included a simple one-touch start-and-stop control panel with a running-hour meter and LED indicators. Remote start-and-stop controls were also supported.

The generator monitors potentially damaging conditions and provides warnings or shutdown protection for:

• Engine overspeed
• Low lubricating-oil pressure
• High exhaust temperature
• High engine-coolant temperature
• Additional monitored operating faults

The standard specification also included an AC circuit breaker and an integral 12-amp battery-charging system.

Automatic shutdowns reduce the risk of major damage but do not replace routine inspection of oil, coolant, raw-water flow, fuel supply, exhaust components, electrical connections, and CO-monitoring equipment. 6.5 MCG 6.5

Quiet 1800 RPM Operation

The Westerbeke 6.5 MCG 6.5 was developed as a low-speed gasoline marine generator.

Its noise- and vibration-control features include:

• 1800 RPM operating speed
• Three-cylinder engine
• Engine balance shaft
• Electronic speed control
• Flexible vibration isolators
• Freshwater-cooled exhaust manifold
• Water-injected exhaust system

Westerbeke noted that 3600 RPM engines are generally noisier and often require sound shielding to achieve comparable sound levels.

Final onboard noise depends on the complete installation, including:

• Generator foundation
• Machinery-space insulation
• Ventilation openings
• Muffler selection
• Exhaust-hose routing
• Flexible connections
• Structural vibration transmission

Dimensions and Installation Requirements

The 6.5 MCG has a compact, low-profile configuration.

The official drawing is marked for reference only. The approved model- and serial-number-specific installation drawing should be used when preparing the generator foundation and final connections. 6.5 MCG 6.5

Installation planning should confirm:

• Machinery-space dimensions
• Mounting-hole positions
• Generator lifting and removal route
• Maintenance access
• Fuel-line routing
• Ignition-protected ventilation
• Raw-water intake position
• Siphon-break requirement
• Wet-exhaust configuration
• Starting-battery cable size
• AC output wiring
• Grounding and bonding
• Shore-power transfer switching
• CO-detector placement

Suitable Marine Applications

Gasoline-Powered Motor Yachts

The 6.5 MCG 6.5 is appropriate for compatible vessels whose propulsion engines and onboard fuel arrangements already use gasoline.

Sport Cruisers

Its compact dimensions and 1800 RPM operation make it suitable for cruisers requiring onboard power for refrigeration, charging, pumps, lighting, electronics, and selected comfort systems.

Houseboats and Liveaboard Craft

The generator may support compatible domestic loads, battery banks, refrigerators, freshwater systems, lighting, outlets, and entertainment equipment.

Passenger and Hospitality Boats

It may provide auxiliary power for lighting, refrigeration, communications, pumps, and passenger-service systems, subject to correct sizing.

Marine Generator Replacement

The 6.5 MCG 6.5 may replace an older gasoline generator when the vessel’s voltage, frequency, fuel, dimensions, weight, ventilation, cooling, exhaust, controls, and wiring are compatible.

Complete Technical Specifications

The specifications are drawn from Westerbeke’s official advanced specification sheet and current legacy-product page. Specifications may differ by serial number or production revision. 6.5 MCG 6.5

Standard Equipment

Original standard equipment included:

• Three-cylinder gasoline engine
• Sequential multiport EFI
• Water-cooled returnless fuel system
• Low-CO catalyst system
• Electronic governing
• One-touch start-and-stop panel
• Running-hour meter and LED indicators
• Safety warnings and automatic shutdowns
• Freshwater cooling and coolant-recovery tank
• AC circuit breaker
• 12-amp battery-charging system
• 90-degree water-injected exhaust elbow
• Belt-driven raw-water pump
• Vibration isolators
• Lubricating-oil drain hose
• Belt guard
• Operator’s manual and parts list

The original literature also stated compliance with USCG regulation 33 CFR 183.

Optional Equipment

Original optional accessories included:

• Remote start-and-stop controls
• Remote lubricating-oil filter
• Onboard spare-parts kit
• Extended-cruising spare-parts kit
• Hydro-Hush muffler and fittings
• Anti-siphon valve with ¾-inch stainless-steel loop
• Ship-to-shore transfer switch
• Auxiliary DC power adapter

Because the model is discontinued, availability of legacy accessories should be confirmed before purchase.

Frequently Asked Questions

Is the Westerbeke 6.5 MCG 6.5 a diesel generator?

No. The 6.5 MCG 6.5 is a gasoline or petrol marine generator with sequential multiport electronic fuel injection.

How much power does it produce?

It produces 6.5 kW at 120V, 60 Hz and 1800 RPM, with a rated current of 54.1 amps.

What does Low-CO mean?

Low-CO means the generator uses precise air-to-fuel control and a catalyst to reduce normal carbon-monoxide emissions. It does not eliminate CO or make the exhaust safe.

Does the catalyst require replacement?

The operator’s manual specifies catalyst replacement every 2,000 operating hours and CO verification seasonally or every 1,000 hours, whichever occurs first. 6.5 MCG 6.5

Is the 6.5 MCG 6.5 still manufactured?

No. Westerbeke currently identifies it as a model that is no longer in production, although technical documents and parts information remain available.

Is it freshwater cooled?

Yes. The engine uses freshwater cooling with a marine heat exchanger and a freshwater-cooled exhaust manifold.

Can it replace another gasoline marine generator?

Potentially, provided the fuel type, voltage, frequency, output, dimensions, weight, ventilation, exhaust, cooling, controls, and electrical distribution are compatible.

Request Pricing and Availability

The Westerbeke 6.5 MCG 6.5 kW 60 Hz Low-CO Marine Gasoline Generator combines compact dimensions, low-speed 1800 RPM operation, sequential multiport EFI, electronic governing, freshwater cooling, a brushless four-pole alternator, and catalytic Low-CO technology.

As this model is discontinued, request confirmation of the generator’s condition, serial number, operating hours, catalyst history, included accessories, warranty coverage, and available replacement parts before ordering.

Contact our marine generator specialists to check the latest Westerbeke 6.5 MCG 6.5 price, available stock, shipping arrangements, and compatibility with your vessel.