Volvo Penta · Inboard diesel

Volvo Penta MD5

The MD5 is Volvo Penta’s single-cylinder diesel with direct raw-water cooling: 0.443 litres, direct injection, the cylinder inclined at 45°, a replaceable wet liner and a hand crank with decompression lever as back-up to the electric starter. MD5A and MD5B give 5.5 kW (7.5 hp) at 2500 rpm and came with the MS reverse gear or the 110S saildrive. The MD5C belongs to Volvo Penta’s 3000 series (with MD7B, MD11D and MD17D): 7 kW (9.5 hp) at 3000 rpm, a 50 A alternator, and the MS2 reverse gear or the 120S saildrive. Most service parts are shared; where they differ (original raw water pump, alternator, belt on later MD5C engines), the notes say so.

Manuals & documents
Wear parts & part numbers
Service intervals
Specifications
Good to know
On the marketplace

Manuals & documents

The links go straight to Volvo Penta. We host no manuals or drawings — the manufacturer’s copy is the current one.

Instruction book MD5A, MD5A/110S (1978, scanned) Operation manual pubs.volvopenta.com · PDF · EN
Product leaflet MD5A (MS reverse gear) Product leaflet pubs.volvopenta.com · PDF · EN
Product leaflet MD5A/110S Product leaflet pubs.volvopenta.com · PDF · EN
Product leaflet MD5B (MS reverse gear) Product leaflet pubs.volvopenta.com · PDF · EN
Product leaflet MD5B/110S Product leaflet pubs.volvopenta.com · PDF · EN
Product leaflet MD5C/MS2 Product leaflet pubs.volvopenta.com · PDF · EN
Product leaflet MD5C/120S Product leaflet pubs.volvopenta.com · PDF · EN
Brochure 3000 series (MD5C, MD7B, MD11D, MD17D) Brochure pubs.volvopenta.com · PDF · EN
Volvo Penta manuals & handbooks: MD5A (workshop manual listed, print only) Manual portal volvopenta.com · EN
Volvo Penta manuals & handbooks: MD5B Manual portal volvopenta.com · EN
Volvo Penta manuals & handbooks: MD5C Manual portal volvopenta.com · EN
Volvo Penta parts catalogue, filtered to MD5A Parts catalogue volvopenta.com · EN
Parts catalogue: raw water pump MD5A/B/C Parts catalogue volvopenta.com · EN
Maintenance quick guide MD5A (Volvo Penta dealer Marine Parts Europe) Parts catalogue marinepartseurope.com · EN

Wear parts & part numbers

Part	OEM number	Also fits	Note
Impeller kit (with gasket)	`21951342`^1,2,3,4,5replaces 3586496	—	Impeller 3586501 with cover gasket 833994. Fits the current pump 858065 and the earlier pumps 833883 (MD5A/B) and 840076 (MD5C).
Pump cover gasket	`833994`^1,6	—	Included in impeller kit 21951342.
Raw water pump	`858065`^1,2,7replaces 833883replaces 840076	—	Current pump for all three versions: 833883 was fitted to MD5A/MD5B, 840076 to MD5C.
Water pump repair kit	`875584`⁸	—	For the earlier pumps 833883 and 840076: shaft, cam, cover, bushing, seals and gasket.
Engine oil filter	`22057107`^9,10,5,11replaces 834337	—	Current number in Volvo Penta’s MD5A and MD5C maintenance quick guide (authorised dealer); the parts catalogue shows 834337.
Fuel filter (engine)	`829913`^12,13,14,15	—	For the filter housings 829912 (engine nos. 50884–57130 in the catalogue) and 840532 (from 57131); 840532 also replaces the original Bosch-type housing 803323.
Fuel filter (engine)	`21492771`^5,11	—	Spin-on filter listed as today’s part in Volvo Penta’s MD5A and MD5C maintenance quick guide. One source only (authorised dealer Marine Parts Europe); the MD5A guide also gives insert kit 23686345.
Fuel filter (engine)	`870065`^16,17	—	Insert only for engines that still have the original Bosch-type housing 803323 (centre screw).
Thermostat	`875783`^18,19,20,5	—	60 °C kit with housing gasket 838013, from engine no. 18374; same kit on MD5A/B and MD5C.
Thermostat gasket	`838013`^18,8	—	Also part of thermostat kit 875783 and gasket set 875561.
Alternator V-belt	`966698`^21,22,23,11replaces 958322	—	1300 mm, for MD5A, MD5B and MD5C up to engine no. 30016. 966698 is the current number in the MD5C quick guide; the parts catalogue shows 958322.
Alternator V-belt	`976492`^22,24,11replaces 958368	—	1325 mm, MD5C from engine no. 30017 (current number from the MD5C quick guide).
Exhaust mixing elbow	`838224`^18,19,25	—	Water-injected elbow, same on MD5A/B and MD5C.
Cylinder head gasket	`838127`^26,8,27	—	Also part of gasket set 875561.
Gasket set	`875561`^8,28	—	Decarbonising (top-end) set: head gasket, valve cover gasket 838066, thermostat gasket, valve stem seal and small seals. Full reconditioning set: 875562.
Injector nozzle	`838287`^29,30	—	Fits both injector versions, 838153 and 838289.
Air filter	`838216`^18,19,31	—	Intake silencer with a cleanable filter, MD5A/B/C.
Gasket set	`875577`^32,33	—	Gasket set for the MS reverse gear (MD5A/MD5B); the MS2 gear of the MD5C takes set 875704.
Saildrive anode	`875812`^{34,35,36,37,38,39}	—	Zinc ring for the 110S saildrive in salt water; magnesium version 876603 for fresh water. 120S (MD5C/120S): zinc anode 851983. With a shaft drive: shaft anode 833913 (25/30 mm shaft) or 833915 (35 mm).

Numbers checked against the sources below on 12 October 2026. Always confirm against your serial number and exact type before ordering.

Service intervals

Task	Interval
First service	After the first 20 h (new or overhauled engine): oil and filter change, re-torque the cylinder head, then set the valve clearance⁴⁰
Engine oil change	Every 50 h and at lay-up; check the level daily⁴⁰
Oil filter	Every 100 h (every second oil change) or at least once a season⁴⁰
Gearbox oil change	MS reverse gear: change every 200 h, check the level every 14 days⁴⁰
Valve clearance	Check and adjust every 50 h (part of the 50-hour service)⁴⁰
Fuel filter	Filter element and feed-pump strainer every 100 h or at least once a season, then bleed the system⁴⁰
V-belt check	Check tension every 14 days (about 5 mm give under thumb pressure midway between the pulleys); check for wear every 100 h or once a season⁴⁰
Raw water impeller	Check the cooling system every 100 h or once a season; inspect the impeller at lay-up⁴⁰
Injectors	Every third year: test opening pressure, spray pattern and leakage (workshop)⁴⁰
Saildrive diaphragm	110S: renew the rubber seals every 5 years⁴⁰
Saildrive anode	110S: replace when more than 50 % has gone; never paint it⁴⁰

From the MD5A instruction book (1978 edition), which Volvo Penta links for the MD5A, MD5B and MD5C. Hours or season, whichever comes first.

Specifications

Versions	MD5A and MD5B (7.5 hp): MS reverse gear or 110S saildrive (MD5A/110S, MD5B/110S); MD5C (9.5 hp, 3000 series): MS2 reverse gear or 120S saildrive (MD5C/120S)^{41,42,43,44,45,46}
Cylinders	1, inclined 45°, four-stroke, direct injection⁴⁰
Displacement	0.443 l (84 × 80 mm)⁴⁰
Power	MD5A/MD5B: 5.5 kW (7.5 hp) at 2500 rpm; MD5C: 7 kW (9.5 hp) at 3000 rpm (at the propeller shaft, DIN 6270 B)⁴⁵
Rated speed	2500 rpm (MD5A/MD5B); 3000 rpm (MD5C)^40,45
Idle speed	approx. 700 rpm (MD5A book)⁴⁰
Compression pressure	2.0–2.2 MPa (284–313 psi) at starter speed⁴⁰
Cooling	Direct raw-water cooling; camshaft-driven pump with neoprene impeller⁴⁰
Thermostat opens at	60 ± 2 °C, fully open at 90 °C⁴⁰
Engine oil capacity	2.0 l without filter, 2.1 l with filter change (MD5A book)⁴⁰
Engine oil grade	API CD diesel engine oil; SAE 20W/30 above +10 °C, SAE 10W below +10 °C (1978 book)⁴⁰
Valve clearance (hot)	Inlet 0.30 mm, exhaust 0.35 mm, set on a warm engine⁴⁰
Injection pressure	18 MPa (180 kp/cm²)⁴⁰
Injection timing	25–28° before TDC⁴⁰
Injection	Bosch injection pump and injector⁴⁰
Alternator	14 V, 35 A (MD5A/MD5B); 50 A (MD5C)⁴⁵
Starter motor	0.8 kW, plus hand crank with decompression lever⁴⁰
Weight	With MS gear approx. 111 kg (MD5A/MD5B); MD5A/110S approx. 128 kg; MD5C/MS2 approx. 116 kg⁴⁵
Gearbox	MD5A/MD5B: MS reverse gear (Mono Shift) 1.91:1 or 110S saildrive 1.66:1. MD5C: MS2 reverse gear 2.4:1 (raw-water cooled, 7° down-angle, built-in slip coupling) or 120S saildrive 2.2:1⁴⁵
Gearbox oil	MS reverse gear 0.55 l, 110S saildrive 1.8 l, both with the same API CD engine oil (MD5A book; it gives no volumes for MS2 and 120S)⁴⁰
Tightening torques	Cylinder head nuts 70 Nm, con-rod bolts 70 Nm, main bearings 70 Nm, flywheel nut 500 Nm, injector nuts 10 Nm⁴⁰
Max. installation angle	15° aft, 20° sideways (max. while running)⁴⁰

Good to know

The impeller is held on its shaft by a bolt: take off the pump cover, draw the shaft out just far enough to reach the bolt, then pull the impeller. If impeller and shaft turn freely together, the rubber drive flange between camshaft and pump is worn, not the impeller.⁴⁰
Change the oil warm by pumping it out through the dipstick tube. The filter only needs replacing at every second change: oil the new seal, screw the filter on until it touches, then half a turn more.⁴⁰
The MS reverse gear has its own small sump with 0.55 l of the same engine oil. Check it every two weeks with the dipstick resting in the hole, not screwed in, and do not overfill.⁴⁰
After any fuel filter or strainer job, open the vent screw on the filter and work the hand primer until fuel comes out without bubbles. If the primer feels dead, turn the engine over a little so the drive cam moves.⁴⁰
Order by engine number: thermostat kit 875783 applies from engine no. 18374, and the MD5C belt changes at no. 30017 (1300 mm before, 1325 mm after).^22,18
To start by hand, lift the decompression lever on the rocker cover, crank the engine up to speed and then drop the lever.⁴⁰

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Sources

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