Market Position:
Compact marine diesel auxiliary engine for recreational and light commercial vessels.
Target Audience:
Boat owners, marine technicians, and DIY mechanics performing maintenance and repairs.
Key Features:
Robust construction, reliable performance, ease of service, and efficient fuel operation.
Competitive Advantage:
Volvo Penta parts and service network, simple two-cylinder design, proven longevity.
Engine Mechanical:
Cylinder head, pistons, connecting rods, crankshaft, bearings, timing gears
Lubrication System:
Oil pump, oil filter, oil passages, pressure relief valve
Cooling System:
Raw water pump, thermostat, cooling passages, zinc anodes
Fuel System:
Fuel pump, injectors, fuel filters, injection timing
Electrical System:
Alternator, starter motor, wiring, sensors
Exhaust System:
Exhaust manifold, riser, muffler, piping
Transmission:
Marine gear (MS/HS series) removal, inspection, reinstallation
Steering and Controls:
Throttle and shift cable adjustment
Propulsion:
Propeller shaft, stuffing box, stern tube
Troubleshooting:
Diagnostic charts for common symptoms
Specifications:
Torque values, clearances, wear limits
Special Tools:
Required tools and part numbers
Procedures Included:
Disassembly, inspection, repair, reassembly, and adjustment steps.
Technical Depth:
Intermediate to advanced; assumes mechanical knowledge.
Parts Information:
Part numbers and component identification, no parts catalog for ordering.
File Format:
PDF (searchable, bookmarked, zoomable)
Compatibility:
Windows, macOS, Linux, iOS, and Android — any device with a PDF reader
Requirements:
A PDF reader application (e.g. Adobe Acrobat Reader, free)
Searchability:
Fully text searchable for fast lookup of any topic
Print Quality:
High-resolution digital pages, printable at full clarity
Binding Type:
N/A — digital download, no physical binding
Paper Type:
N/A — digital download, no physical paper
Engine Options:
MD6A and MD7A
Configuration:
Inline two-cylinder, four-stroke, direct injection
Displacement:
MD6A: 1.0 L; MD7A: 1.3 L (approximate)
Bore x Stroke:
MD6A: 76 mm x 90 mm; MD7A: 84 mm x 90 mm (approximate)
Power Output:
MD6A: 12.5 kW (17 hp); MD7A: 17 kW (23 hp) at 2500 rpm (approximate)
Torque:
Not specified in available data
Fuel System:
Mechanical direct injection, Bosch style pump
Cooling:
Raw water cooled
Length:
Not specified in available data
Width:
Not specified in available data
Height:
Not specified in available data
Dry Weight:
MD6A: ~180 kg; MD7A: ~200 kg (approximate with marine gear)
Wheelbase:
Not applicable (marine engine)
Crash Test Ratings:
Not applicable (marine engine)
Active Features:
Overheat alarm, low oil pressure alarm, and engine shutdown systems (where fitted).
Passive Features:
Guards on rotating parts, insulated exhaust, and flame arrestor.
Service Intervals:
Oil and filter: every 100 hours or annually; fuel filters: every 200 hours; impeller: annually or as needed.
Fluid Specifications:
Engine oil: SAE 15W-40 API CD or better; transmission oil: SAE 30 or ATF as specified.
Known Issues:
Raw water pump impeller wear, exhaust elbow corrosion, fuel injector fouling, and oil leaks from seals.
Common Wear Items:
Impeller, zinc anodes, belts, hoses, and filters.
Manufacturer:
Volvo Penta, a division of Volvo Group
Brand Heritage:
Swedish engineering, marine propulsion since 1907.
Model Evolution:
MD6A and MD7A were part of the MD series, succeeded by MD11, MD17, etc.
Production Location:
Sweden
