Honda · Outboard

Honda BF20

The BF20D and BF15D are Honda’s 350 cc two-cylinder four-stroke portables, built since 2003 and still in the range; this page covers both. They are common on larger tenders and as auxiliaries on small yachts: about 46–49 kg with tiller and recoil start, with 15, 20 or 25 in shafts, tiller or remote control, recoil or electric start, manual or power tilt. The BF15D is the same engine rated at 15 hp, and the Power Thrust versions BFP15D/BFP20D (plus the BFP9.9D, the same engine detuned) carry a four-blade 10 × 7-5/8 in propeller for heavy boats. The older BF15A/BF20A (before 2003) are different engines and are not covered here.

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

Manuals & documents

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

Owner’s manual BF15D / BFP15D / BF20D (current edition, serials BALJ/BAMJ-1600001 on) Operation manual cdn.powerequipment.honda.com · PDF · EN
Owner’s manual BF15D / BFP15D / BF20D / BFP20D (2009 edition, serials 1400001–1499999) Operation manual cdn.powerequipment.honda.com · PDF · EN
Owner’s manual BF15D / BFP15D / BF20D / BFP20D (first edition 2003, serials 1000001–1099999) Operation manual cdn.powerequipment.honda.com · PDF · EN
Honda Marine (US): BF20 owner’s manuals by serial range Manual portal marine.honda.com · EN
Honda Marine (US): BF15 owner’s manuals by serial range Manual portal marine.honda.com · EN
Honda Motor Europe owner’s manual portal (choose model and language) Manual portal honda.co.jp · EN
Shop manual BF15D / BFP15D / BF20D / BFP20D (61ZY000E5, printed, for purchase) Service manual publications.powerequipment.honda.com · EN
Parts catalogue BF15DK3 / BFP15DK3 / BF20DK3 (14ZY0C01P, printed, for purchase) Parts catalogue publications.powerequipment.honda.com · EN
BF15/BF20 model page with specifications (Honda Marine US) Product page marine.honda.com · EN
BF15/BF20 specifications (Honda UK) Product page honda.co.uk · EN

Wear parts & part numbers

Part	OEM number	Also fits	Note
Raw water pump impeller	`19210-ZW9-A32`^1,2,3,4replaces 19210-ZW9-A31replaces 19210-ZW9-A30	—	Fits every BF15D/BF20D generation (D3 to DK2 on the fiche), the BFP versions and the BF8D/BF9.9D/BF10D.
Impeller kit (with gasket)	`06192-ZW9-A32`^5,6replaces 06192-ZW9-A30	—	Impeller, cover gasket, O-ring and Woodruff key; listed from BF15D3/BF20D3 to BF15DK2/BF20DK2.
Water pump repair kit	`06193-ZY1-030`^5,6replaces 06193-ZY1-010replaces 06193-ZY1-000	—	Rebuild kit including the pump housing. The BF20DK2 fiche lists -010, the BF20D3 fiche -000; both now come as -030. One source (one dealer’s Honda fiche).
Pump cover gasket	`19232-ZW9-000`^2,3	—	Same number for BF20D3 and BF20DK2. Water tube seal 19253-ZW9-000, pump housing O-ring 91351-ZW9-000. One source (one dealer’s Honda fiche).
Engine oil filter	`15400-ZZ3-003`^7,8,9replaces 15400-PFB-014replaces 15400-PFB-004replaces 15400-PFB-007replaces 15400-ZW4-003replaces 15400-PJ7-015	—	Current number; the older numbers on the BF20D3 and BF20DK2 fiche lead to it.
Spark plug	`NGK CR5EH-9`^10,11,12,13	Denso `U16FER9`¹⁰	Two per engine; Honda number 98059-55916. Gap 0.8–0.9 mm, 12 N·m.
Thermostat	`19300-ZW9-003`^14,15,16,17	—	Also used on the BF8D to BF50D and larger Hondas; cover O-ring 19317-ZW9-000.
Anode (lower unit)	`41106-ZW9-000`^18,19,20	—	Two per engine, on the gear case and the extension case; the same anode fits the BF8D to BF50D.
Anode (engine)	`12155-ZV4-A01`^15,16replaces 12155-ZV4-A00	—	Small anode in the thermostat housing — the “anode inside engine” of the service schedule. One source (one dealer’s Honda fiche).
Fuel filter (engine)	`16910-ZV4-015`^21,22,23replaces 16910-ZV4-005	—	In-line strainer under the cowl, ahead of the fuel pump; the same part is used from the BF8D to the BF100A. One source (one dealer’s Honda fiche).
Fuel pump	`16700-ZW9-003`^22,23	—	Diaphragm pump, same number for BF20D3 and BF20DK2; O-ring 91303-ZW9-000. One source (one dealer’s Honda fiche).
Timing belt	`14400-ZY1-013`²⁴replaces 14400-ZY1-003	—	Belt marked 71RU13; unchanged from BF15D3/BF20D3 to BF15DK2/BF20DK2. Dealer job. One source.
Valve cover gasket	`12312-ZW9-000`^12,13	—	Needed for the valve clearance check; the head gasket is 12251-ZY1-003. One source (one dealer’s Honda fiche).
Propeller nut	`90301-ZV4-000`^25,26	—	10 mm castle nut; split pin 3 mm 90758-ZV4-000, thrust washer 90501-ZW9-C00 (was 90501-ZW9-010). One source (one dealer’s Honda fiche).
High-thrust propeller (4-blade)	`58130-ZY0-B92ZA`^27,25,26	—	Power Thrust 4-blade 10 × 7-5/8 in, as on the BFP versions (kit 06581-ZY0-S00ZB). The fiche also lists 4-blade 9-1/4 × 11 in (58130-ZW9-V42ZA, BF20DK2) and 9-1/4 × 7 in (58130-ZW9-V02ZA, was V01ZA, BF20D3). One source (one dealer’s Honda fiche).

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
Oil level check	Before each use²⁸
Engine oil change	Every 100 h or 6 months, first after 20 h or 1 month²⁸
Gear oil change	Every 100 h or every 6 months, first time after 20 h²⁸
Oil filter	Every 200 h or yearly²⁸
Spark plug	Check and re-gap every 100 h or 6 months; replace every 200 h or yearly²⁸
Fuel filter	In-line filter: check every 100 h or 6 months, replace every 200 h or yearly; clean the fuel tank and tank filter every 200 h or yearly²⁸
Hoses & clamps	Fuel line: check before each use; replace every 2 years if necessary²⁸
Raw water impeller	Water pump: check every 200 h or yearly (dealer); watch the tell-tale at every start²⁸
Thermostat	Check every 200 h or yearly²⁸
Valve clearance	Check and adjust every 200 h or yearly (dealer)²⁸
Timing belt	Check every 200 h or yearly (dealer)²⁸
Anode	Outside anodes: check before each use; anode inside the engine: check every 400 h or 2 years; replace once only about a third is left or it crumbles²⁸
Lubrication	Grease every 100 h or 6 months, first after 20 h; more often in salt water²⁸
Carburettor	Linkage and idle speed, plus bolts and nuts: check and adjust after the first 20 h, then every 100 h or 6 months²⁸
Cooling system	Flush with fresh water after every use in salt, muddy or murky water²⁸

Hours or months, whichever comes first. The schedule is from Honda’s BF15D/BF20D owner’s manual (2009 edition, serials 1400001–1499999); the current 2024 edition lists the same items and adds a shift cable check. “Dealer” marks the jobs Honda leaves to a workshop.

Specifications

Cylinders	2 in line, four-stroke OHC, 4 valves, water-cooled¹⁰
Displacement	350 cc (59 × 64 mm)²⁹
Power	BF20D: 14.9 kW (20 hp); BF15D: 11.2 kW (15 hp), at the propeller shaft¹⁰
Full-throttle range	BF20D 5000–6000 rpm; BF15D 4500–5500 rpm¹⁰
Idle speed	900 ± 50 rpm¹⁰
Cooling	Raw-water cooled with thermostat; impeller pump in the lower unit, tell-tale outlet; exhaust through the propeller hub¹⁰
Engine oil capacity	1.0 l, 1.1 l with filter change (manuals from serial BALJ/BAMJ-1400001; the 2003–2005 manuals give 1.3 l with filter)^10,11
Engine oil grade	Honda 10W-30 FC-W outboard oil, or SAE 10W-30 to API SG, SH or SJ¹⁰
Gear oil capacity	0.29 l¹⁰
Gear oil grade	SAE 90 hypoid gear oil, API GL-4 (older manuals: GL-4 or GL-5)¹⁰
Spark plug	NGK CR5EH-9 or Denso U16FER9 (2), gap 0.8–0.9 mm¹⁰
Valve clearance (cold)	Intake 0.17 ± 0.02 mm, exhaust 0.23 ± 0.02 mm¹⁰
Tightening torques	Spark plugs 12 N·m, gear oil drain and level screws 6.5 N·m¹⁰
Fuel	Unleaded petrol, RON 91 or higher (AKI 86); one carburettor with diaphragm fuel pump; separate 12 l tank¹¹
Alternator	12 V / 6 A charge coil (recoil start), 12 V / 12 A (electric start)¹⁰
Gearbox	F-N-R dog clutch, 2.08:1²⁹
Shaft length	S 15 in (381 mm), L 20 in (508 mm), X 25 in (635 mm); transom 433 / 563 / 703 mm at 12° trim²⁹
Dry weight	BF20D with propeller: 46 kg (S, tiller, recoil start), 49 kg (L, tiller, recoil start); electric start 49–57.5 kg, power tilt up to 59.5 kg¹⁰
Propeller	Standard 3-blade 9-1/4 × 10 in; Power Thrust (BFP) 4-blade 10 × 7-5/8 in²⁹
Tilt	Manual tilt: 5 trim positions (4–20°), tilt stops at 22°, 37° and 64°; gas-assist (G) and power tilt (T): 4 trim positions, stepless up to 64°¹⁰
Years built	From 2003 (BF20D3), DK2 from 2011; still in production^11,29

Good to know

Look for the tell-tale stream every time you start. If it weakens or stops, check the intake screens and the impeller before running on. On longer trips, carry the impeller kit 06192-ZW9-A32.^10,5
After every trip in salt, muddy or murky water, flush the cooling passages with fresh water. Honda asks for it, and it is the cheapest way to keep the thermostat and the water jacket clean.¹⁰
The sump holds only about a litre, so measure the oil instead of pouring by feel — Honda warns that too much makes the engine smoke and leak. With a filter change the current manuals give 1.1 l; the early ones said 1.3 l.^10,11
When laying the motor up, cover the timing belt before you spray corrosion inhibitor under the cowl — the manual warns that a soaked belt can fail.¹⁰
Replace the anodes once only about a third is left or they start to crumble. There are two outside, on the gear case and the extension case, and a small one inside the thermostat housing that is easy to forget.^28,19,15

Fitted in

Boats whose builder lists it as standard or optional equipment:

Lagoon 42 — Honda BF20 (Option: dinghy set CL 340 with Honda BF20 outboard, configurator 2019, 2020 and 2022)

On the marketplace

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Sources

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