Yamaha · Outboard

Yamaha F4, F5 & F6

Yamaha’s F4, F5 and F6 are one engine in three power ratings: a 139 cc single-cylinder OHV four-stroke with recoil start, tiller steering and forward, neutral and reverse, weighing 27 kg with the short shaft. A 1.1 l tank is built in, a 12 l remote tank can be connected, and the motor can be laid down on three sides without oil running out. It is a common dinghy and tender motor and an auxiliary on small sailing boats, and all three ratings share the same wear parts. The F4B and F6C replaced the 112 cc F4A and the heavier F6A/F6B in 2010 and were joined by the F5A; a second series with new model codes followed in 2014, and the current European manual calls them F4MHA, F5MHA and F6MHA (F4SMHA, F5SMHA and F6SMHA in North America).

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

Manuals & documents

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

Owner’s manual F4, F5, F6 (6EC-28199-71, November 2025) Operation manual cdn2.yamaha-motor.eu · PDF · EN · DE · FR · ES
Owner’s manual F4B, F5A, F6C (6EC-F8199-71-E0, February 2015) Operation manual cdn2.yamaha-motor.eu · PDF · EN
Owner’s manual F2.5A, F4B, F5A, F6C, first series (6BV-F8199-74-E0, November 2013) Operation manual cdn2.yamaha-motor.eu · PDF · EN
Yamaha Motor Europe owner’s manual library (outboards, all years and languages) Manual portal yamaha-motor.eu · EN
Yamaha Motor Europe parts catalogue Parts catalogue yamaha-motor.eu · EN
Yamaha Outboards (US): owner’s manuals by model code and serial number Manual portal yamahaoutboards.com · EN
Yamaha Outboards (US): F6, F4 and F2.5 model page with specifications Product page yamahaoutboards.com · EN
Yamaha parts fiche F6CMHS 2015 (model code 6EE2) Parts catalogue yamaha-parts.ca · EN
Yamaha parts fiche F5AMHS 2015 (model code 6ED2) Parts catalogue yamaha-parts.ca · EN
Yamaha parts fiche F4BMHL 2015 (model code 6EC2) Parts catalogue yamaha-parts.ca · EN

Wear parts & part numbers

Part	OEM number	Also fits	Note
Raw water pump impeller	`6E0-44352-00-00`^1,2,3	—	The same impeller on every F4B, F5A and F6C fiche from 2011 to 2021 and on the older 112 cc F4A (68D); the F6A/F6B used a different one (68T-44352-00-00). Dealers often shorten the number to 6E0-44352-00.
Water pump repair kit	`6EE-W0078-02-00`^4,5,6replaces 6EE-W0078-00-00replaces 6EE-W0078-01-00	—	Pump housing 6BX-44311-00-00, gasket 6EE-44315-00-00, cartridge insert 6BX-44322-00-00, outer plate 6BX-44323-00-00, impeller 6E0-44352-00-00, water seal damper, bolt and dowel pin. US dealers still sell the earlier issues.
Spark plug	`94702-00372-00`^7,5,8	NGK `CR6HSB`⁷	An NGK CR6HSB under Yamaha’s number. Gap 0.6–0.7 mm, 13 N·m. The same plug in both series; the older F4A took an NGK BR6HS (94701-00248-00).
Thermostat	`66M-12411-01-00`^9,10,11	—	Sits on its seal under the thermostat cover. Yamaha uses the same thermostat on the F2.5 to F15 portables and on the older F4A and F6A.
Thermostat gasket	`67D-12414-A0-00` · `688-12412-00-00`^5,9	—	Cover gasket 67D-12414-A0-00 (the thermostat cover also closes off the internal anode) and the thermostat seal 688-12412-00-00. Yamaha’s maintenance-parts list names only the cover gasket.
Anode (engine)	`6G8-11325-00-00`^5,12,13	—	Small internal anode in the cooling jacket, under the thermostat cover; replace it every 500 h or 5 years. The same part on all F4B/F5A/F6C and on the older F4A.
Anode (lower unit)	`6L5-45251-03-00`^14,15replaces 6L5-45251-02-00replaces 68D-G5251-00-00	—	Bolted to the gear case, 9 N·m. Dealers list it for the F5AMHS, F6CMHS, F6SMHA and F6LMHA among others.
Fuel filter (engine)	`68T-24251-01-00`^16,17,18replaces 6EE-F4251-00-00	—	In-line filter in the bottom cowling, between the fuel cock and the fuel pump (Yamaha: ‘Strainer 1’). Also fitted to the F8 and F9.9 portables.
Inlet strainer	`6BX-24167-00-00`^19,20	—	Fuel tank strainer in the filler neck of the built-in tank; clean it when dirt collects in it.
Engine oil strainer	`51Y-13411-00-00`^21,5,22replaces 5YP-E3411-00-00	—	Engine oil strainer in the crankcase — there is no spin-on oil filter. It sits under a cover with gasket 6EE-13475-00-00 and is cleaned by the dealer every 100 h.
Gear oil plug gaskets	`90430-08003-00`^1,5,23replaces 90430-08020-00replaces 90430-08801-00	—	Two per change, under the gear oil drain screw and the level plug (90340-08002-00); renew both at every gear oil change.
Carburettor repair kit	`6BX-W0093-00-00`^24,25,26	—	Float, float chamber gasket, needle valve, float pin, clip, screw and O-ring; the same kit on the F4 and F6 fiches. The complete carburettor on the 2015 F6 fiche is 6BX-14301-00-00 (main jet #75, pilot jet #42).
Gasket set	`6EE-W0001-00-00`^27,28	—	Power head gasket kit: head gasket, cylinder gasket, manifold gaskets, oil seals and O-rings.
Lower unit seal kit	`6EE-W0001-20-00`^4,29	—	Lower unit gasket kit: oil seals, water pump gasket, lower casing packing and O-ring.
Propeller	`6E0-45941-01-00`^14,30,31	—	Aluminium 3-blade 7-1/2 × 8 in (BA mark), on every F4B/F5A/F6C fiche from 2011 to 2021 and on the older F4A. The other pitches are under propeller sizes; pick the one that lets the engine reach the upper half of its full-throttle range with your usual load.
Propeller hardware kit	`6L5-45616-00-00` · `91490-25030-00`^14,32,33	—	Castle nut and cotter pin; the plate washer is 90201-08M54-00 and the thrust washer in front of the propeller 6L5-45987-01-00. Use a new cotter pin every time. Numbers from Yamaha’s dealer fiches only, not cross-checked elsewhere.
Fuel pump	`6BX-24410-01-00`^16,34	—	Diaphragm pump; the diaphragm alone is 6BX-24411-00-00, the primer bulb 6BX-24360-00-00. The same numbers on the 2015 F5 and F6 fiches; not cross-checked elsewhere.

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
Engine oil change	First after 20 h or 3 months, then every 100 h or yearly⁷
Strainer clean	Engine oil strainer: check and clean every 100 h or yearly (dealer)⁷
Gear oil change	First after 20 h or 3 months, then every 100 h or yearly⁷
Spark plug	Check, clean or replace every 100 h or yearly; plug cap and lead checked after 20 h and then every 100 h⁷
Raw water impeller	Impeller and pump housing: check every 100 h or yearly, replace every 300 h or 3 years (dealer)⁷
Thermostat	Check every 100 h or yearly, replace if needed⁷
Fuel filter	In-line filter: replace every 100 h or yearly; tank strainer: check and clean every 100 h; fuel lines checked after 20 h and then every 100 h⁷
Anode	Outer anode: check every 100 h or yearly, replace when worn; internal anode: check every 100 h, replace every 500 h or 5 years⁷
Valve clearance	Check and adjust every 500 h or 5 years⁷
Propeller	Propeller, nut and cotter pin: check after 20 h, then every 100 h or yearly⁷
Lubrication	After 20 h, then every 100 h or yearly: Yamaha grease A on the greasing points, grease D or Yamalube marine grease on the propeller shaft⁷
Full service	Fuel pump: check or replace every 300 h or 3 years; exhaust guide and exhaust manifold: check every 1000 h⁷

Hours or months, whichever comes first. The schedule is from Yamaha’s owner’s manual for the F4, F5 and F6 (6EC-28199-71-E0, November 2025), which assumes about 100 h of use a year. Under hard use — long idling or trolling, short runs from cold, salt water without flushing — Yamaha halves the intervals.

Specifications

Cylinders	1, four-stroke OHV, 2 valves⁷
Displacement	139 cc (62 × 46 mm)⁷
Compression ratio	8.9:1³⁵
Power	F4: 2.9 kW (4 hp); F5: 3.7 kW (5 hp); F6: 4.4 kW (6 hp), at the propeller shaft⁷
Full-throttle range	F4: 4000–5000 rpm; F5 and F6: 4500–5500 rpm⁷
Idle speed	1450–1550 rpm in neutral⁷
Starting	Recoil starter; CDI ignition; carburettor with choke⁷
Cooling	Raw-water cooled: rubber impeller pump on the drive shaft, thermostat, tell-tale outlet⁷
Engine oil capacity	0.6 l (0.63 US qt); dipstick on the filler cap⁷
Engine oil grade	Yamalube 4 (US: Yamalube 4M) or four-stroke outboard oil, SAE 10W-30, 10W-40 or 5W-30, API SE to SL; the 2015 manual also allows SAE 15W-40, 20W-40 or 20W-50 (API SH/SJ/SL) in warm climates^7,36
Gear oil capacity	0.1 l (100 ml)⁷
Gear oil grade	Yamalube outboard gear oil or hypoid gear oil SAE 90, API GL-4⁷
Spark plug	NGK CR6HSB⁷
Spark plug gap	0.6–0.7 mm (0.024–0.028 in)⁷
Valve clearance (cold)	Intake and exhaust 0.08–0.12 mm⁷
Gearbox	Forward, neutral, reverse; 2.08:1 (27/13)⁷
Tilt	Manual tilt up to 69°; trim −4° to +16°; steering 90° each way³⁵
Shaft length	S 15 in, L 20 in (transom height 435 / 562 mm)⁷
Dry weight	27 kg (S) / 28 kg (L), with aluminium propeller⁷
Fuel	Unleaded petrol, at least 90 RON (US: 87 pump octane, max. 10 % ethanol); built-in 1.1 l tank, optional 12 l remote tank⁷
Alternator	None as standard; a lighting coil kit with rectifier/regulator (6 A) can be fitted by a dealer³⁵
Tightening torques	Spark plug 13 N·m, oil drain bolt 18 N·m⁷
Propeller sizes	Aluminium 3-blade, spline, BA mark: 7-1/4 × 6-1/2 in (6E0-45949-00-00), 7-1/2 × 7 in (6E0-45943-01-00), 7-1/2 × 8 in (6E0-45941-01-00), 7-1/4 × 8-1/4 in (6E0-45952-00-00), 7-1/2 × 9 in (6E0-45954-00-00)^14,30
Models	Europe: F4BMH, F5AMH, F6CMH with S or L shaft (e.g. F6CMHS, F6CMHL), in the November 2025 manual F4MHA, F5MHA, F6MHA; North America: F4SMHA, F4LMHA, F5SMHA, F6SMHA, F6LMHA. Model code on the serial label: 6BV (F4B) and 6BX (F6C) for the first series, 6EC (F4B), 6ED (F5A) and 6EE (F6C) from 2014^7,37,38,35
Years built	From 2010 (first series, model codes 6BV/6BX); second series (6EC/6ED/6EE) from 2014; still current^39,38,37

Good to know

One engine, three badges: since 2010 the F4, F5 and F6 have used the same impeller, thermostat, spark plug, filters, anodes, propellers and carburettor kit, so a part sold for a Yamaha F6 fits the F4 just as well. The older 112 cc F4A and the F6A/F6B are different engines — check their own fiches.^5,12
Before ordering, read the model code on the serial label: 6BV and 6BX are first-series engines (from 2010), 6EC, 6ED and 6EE those from 2014. The service parts are the same, but casings and fuel-system details follow the fiche of your year.^38,37
Change the oil with the engine warm and upright: suck it out through the filler with an oil changer, or take out the drain bolt and refit it with a new gasket (18 N·m). The sump only takes 0.6 l, so measure it — too much oil can leak out.⁷
The gearcase takes just 100 ml of SAE 90 GL-4: drain it, then pump new oil in through the lower hole until it comes out of the level hole, with new gaskets on both plugs. Milky oil means water has got past the seals — have the lower unit checked before the gears suffer.⁷
Grease the propeller shaft with a corrosion-resistant grease, fit the thrust washer before the propeller and use a new cotter pin every time — a reused pin can let the propeller come off. Hold the propeller with a block of wood, not your hand, while you undo or tighten the nut.⁷
Before laying it up, run the carburettor dry and drain the built-in tank, put a teaspoon of engine oil into the cylinder through the plug hole and pull the starter a few times; then change the gear oil so no water stays in the gearcase over the winter.⁷

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Sources

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