Yamaha F115
115 HP · Raw-water cooled with thermostatic control; water pump and impeller in the lower unit
The Yamaha F115 is a 115 hp four-stroke petrol outboard and the largest engine on Yamaha's 1.8-litre in-line four platform, which it shares with the F75 and F90. It turns up on bay boats, aluminium fishing boats, pontoons and small centre-consoles, single and in pairs. Maintenance runs on a 100-hour or annual cycle after a 20-hour break-in service, with the external fuel/water separating filter on a shorter 50-hour clock and the timing belt on a five-year one. Below are Yamaha's published specifications, its four-stroke maintenance schedule, and the service part numbers Yamaha publishes for this engine.
Specifications
| Engine type | Four-stroke petrol outboard, inline 4 |
|---|---|
| Displacement | 1.8 L |
| Prop shaft horsepower | 115 hp @ 5500 rpm |
| Full throttle rpm range | 5300–6300 rpm |
| Bore × stroke | 81 × 88.9 mm (3.19 × 3.5 in) |
| Compression ratio | 10.0:1 |
| Fuel induction | EFI |
| Ignition | TCI microcomputer |
| Recommended fuel | 87 octane, 10% ethanol maximum |
| Recommended engine oil | Yamalube 4M FC-W (5W-30 or 10W-30; 20W-40 warm climates only) |
| Engine oil capacity | 3.2 L / 3.0 L (Yamaha model page); 3.4 US qt with filter (Yamaha brochure) |
| Spark plug | NGK LKR6E |
| Alternator output at W.O.T. | 35 A |
| Gear ratio | 2.15:1 |
| Gearcase lubricant capacity | 25.7 fl oz standard rotation; 24.2 fl oz counter-rotation (LF115) |
| Shaft length | 20" / 25" |
| Weight | 171 kg (377 lb) – 175 kg (386 lb) |
| Starting system | Electric |
| Emissions | CARB 3-Star |
Maintenance schedule
Yamaha's recommended service intervals for this engine. Most items are time-or-hours, whichever comes first — boats that sit still hit the calendar interval long before the hours.
Continuous use — at every fill-up and after every outing
- Add Yamalube Ring Free PLUS fuel additive at every fill-up
- Treat every tank with Yamalube Fuel Stabilizer & Conditioner PLUS
- Flush the cooling system after each use, especially in salt or brackish water
- Check the power trim and tilt fluid level, and top up with Yamalube Performance Power Trim & Tilt Fluid if the system will not hold a tilt
- Apply Yamalube Yamashield corrosion-protection spray
- Before going out, inspect the outside of the lower unit for damage and clear any fishing line or debris from the propeller shaft
- During wash-down, brush growth off the anodes — an anode covered by growth, paint or coating cannot do its job
After the first 20 hours — new-outboard break-in service
- Change the engine oil and replace the oil filter
- Replace the lower-unit (gearcase) lubricant, fitting new crush washers to the drain and vent screws
- Replace the external 10-micron fuel/water separating filter
- Replace the primary on-engine fuel filter element
Every 50 hours
- Replace the external 10-micron fuel/water separating filter — or sooner if you take on a bad tank of fuel
Every 100 hours or annually, whichever comes first
- Change the engine oil and replace the oil filter
- Replace the lower-unit (gearcase) lubricant — the drain and vent screw crush washers are single-use and must be renewed every time
- Replace the primary on-engine fuel filter element
- Pull the spark plugs and check them for colour and wear — they should be light brown with relatively sharp edges — and replace as necessary
- Check the magnetic gearcase drain screw while the lubricant drains: fine metallic dust is normal, but larger chips mean a dealer should look for internal damage
Every year — water pump inspection
- Inspect the impeller and water pump assembly, whether the engine runs in salt, brackish, turbid or fresh water
- Replace the impeller or the whole water pump assembly rather than attempting a repair, and never turn the crankshaft or drive shaft counter-clockwise while the pump is apart
Every 300 hours — authorised Yamaha dealer
- Have an authorised Yamaha Marine dealer replace the Vapor Separator Tank (VST) filter
Every 1000 hours or five years, whichever comes first
- Replace the timing belt
Dealer-performed checks — interval per your engine's owner's manual
- Have an authorised Yamaha Marine dealer check the valve clearance
- Have an authorised Yamaha Marine dealer inspect the timing belt
On condition — anodes
- Replace the anodes when they are about half gone — this is owner-serviceable on most models
- Never paint or coat an anode, and brush growth off it at each wash-down: a covered anode cannot protect the engine
Before winter storage or lay-up
- Change the engine oil and replace the oil filter
- Replace the lower-unit (gearcase) lubricant
- Replace the external 10-micron fuel/water separating filter and the primary on-engine fuel filter element
- Treat the fuel with Yamalube Ring Free PLUS and Yamalube Fuel Stabilizer & Conditioner PLUS
- Fog the engine with Yamalube EFI Engine Storage Fogging Oil
- Flush the cooling system and apply Yamalube Yamashield
Genuine service parts
Yamaha part numbers for the routine service items on this engine. Several vary by build date or cooling type — check the note before ordering. Genuine parts are stocked by the Yamaha dealer network; where a cross-reference is shown, an aftermarket equivalent is also available.
| 100-hour service kit | 6HV-W006B-00-00 Yamaha's second-generation 100-hour kit for the 1.8 L family — it fits F75LB, F90LB, F90XB, F90JB, F115JB, F115LB, F115XB, LF115XB, VF90LB, VF90XB, VF115LB and VF115XB. One box holds the oil filter, the engine oil drain plug gasket, the primary fuel filter element and its O-ring, two lower-unit drain plug gaskets and a propeller cotter pin — which is every consumable the 100-hour service needs except the oil and the gearcase lube. Check your model code on the clamp-bracket label against that list before ordering. |
|---|---|
| Oil filter | 5GH-13440-71-00 Yamaha lists this one filter across the whole 1.8 L family — F75, F90 and F115, the VF90 and VF115 V MAX SHO models, and the jet-drive F90 and F115. The table it comes from is headed “Current Engines Only”, so if your outboard is an older serial, confirm the number against the manual for your engine before ordering. |
| Primary on-engine fuel filter element | 6D8-WS24A-00-00 The see-through filter with the water trap on the powerhead — replace it every 100 hours. Yamaha lists the same element for the whole 1.8 L family, and notes that other fuel filters may also be fitted to a given engine, so check yours against the manual for your serial. |
| Engine oil | Varies by configuration Yamalube 4M FC-W four-stroke marine oil. Yamaha states 5W-30 and 10W-30 are correct for all climates and 20W-40 is for consistently warm climates only. The model page gives 3.2 L / 3.0 L and the maintenance brochure gives 3.4 US quarts with filter for the F115 row — the same quantity expressed two ways rather than a contradiction, but fill to the dipstick either way. Yamaha publishes no part number for the oil itself. |
| External 10-micron fuel/water separating filter | Varies by configuration Yamaha specifies its 10-Micron Fuel/Water Separating Filter for the propeller-drive F115, plumbed into the fuel line between tank and engine, and gives it the shortest interval on the engine — 50 hours, or straight away after a bad tank of fuel. Note that the F115 row is not one of the rows Yamaha marks as also accepting the smaller mini-10 filter; the 80 hp jet-drive F115 is. Yamaha names the product but publishes no part number for it; order by name through a dealer. Fill the new filter about three-quarters full with fresh stabilised fuel before fitting to make priming easier. |
| Spark plugs | NGK LKR6E Yamaha's model page and its maintenance brochure agree on this plug for the F115, which is not true of every engine in the range — it is a different plug from the F90's despite the shared powerhead, so do not order by family. Yamaha publishes no plug gap for this engine; do not carry one across from another model. |
| Gearcase (lower unit) lubricant | Varies by configuration Yamalube Marine Gearcase Lube — the standard grade, not the HD grade, which Yamaha restricts to the 200-250 hp, 4.2 L Offshore and XTO models. Capacity is 25.7 fl oz for a standard-rotation F115 and 24.2 fl oz for the counter-rotating LF115, so check which one you have before buying. Yamaha publishes no part number for the lubricant on its public pages. The jet-drive F115 has a jet pump in place of a lower unit and this item does not apply to it. |
| Gearcase drain and vent screw crush washers | Varies by configuration Commonly sold as drain plug gaskets. Yamaha is explicit that these are not reusable and must be replaced every time a drain or vent screw comes out — a flattened washer put back is the usual reason a gearcase weeps after a lube change. Two of them come in the 6HV-W006B-00-00 service kit above, which is the only manufacturer source that supplies them; Yamaha publishes no standalone part number. If you do not see one on the screw, it is probably still stuck to the outboard; pick it free. |
| Engine oil drain plug gasket | Varies by configuration The easiest part on the engine to forget, because it looks reusable and is not. Yamaha includes one in the 6HV-W006B-00-00 kit for every oil change and publishes no standalone part number for it. |
| Water pump impeller / water pump assembly | Varies by configuration Yamaha's published guidance is to INSPECT the impeller and pump assembly every year and to replace the impeller or the whole assembly rather than repair it — it publishes no fixed replacement hours and no part number on its public pages. On an outboard the pump sits in the lower unit, so this is a gearcase-off job. Never turn the crankshaft or drive shaft counter-clockwise with the pump apart. |
| Sacrificial anodes | Varies by configuration Yamaha describes its anodes as “a blend of high-quality alloys” and does NOT publish the fresh/brackish/salt material split that circulates elsewhere — there is no Yamaha magnesium-versus-aluminium-versus-zinc choice to make here. The rule Yamaha does publish is a condition, not an interval: replace them when they are about 50% gone. They sit on the lower unit just above the propeller and on the bottom of the engine bracket. Never paint or coat them. |
| Timing belt | Varies by configuration Yamaha recommends replacing four-stroke outboard timing belts every five years or 1000 hours, and routes the inspection to a dealer. The belts are cogged and Kevlar-impregnated, so they do not stretch and give little warning; do not try to flip a belt to extend its life, and keep lubricant and spray-on products off it. No part number is published on Yamaha's public pages. |
| Vapor Separator Tank (VST) filter | Varies by configuration Attached to the electric fuel pump inside the VST, filtering fuel again before it is pressurised into the injection rail. Yamaha routes this one to the dealer at every 300 hours, and notes that the interval assumes the external 10-micron and on-engine filters have been serviced properly and the fuel treated. No part number is published on Yamaha public pages. |
| Power trim and tilt fluid | Varies by configuration Yamalube Performance Power Trim & Tilt Fluid. Yamaha publishes no change interval for it — the guidance is to check the level and top up if the system will not hold a tilt with the engine stored or running. Order by product name; no part number is published on Yamaha public pages. |
What owners watch
A counter-rotating LF115 takes less gearcase lube than an F115
Yamaha publishes 25.7 fl oz for the standard-rotation F115 and 24.2 fl oz for the counter-rotating LF115. That is a small difference in absolute terms and an easy one to get wrong on a twin installation, where one engine of the pair is the counter-rotating one and both get serviced on the same afternoon. The model code on the clamp-bracket label is the tell: a leading L means counter-rotation. Fill until lubricant appears at the vent hole rather than measuring out a bottle, and treat the published figure as the check rather than the target.
Same powerhead as the F90, different spark plug
The F75, F90 and F115 are one 1.8-litre in-line four, and Yamaha lists a single oil filter, on-engine fuel filter element and 100-hour service kit across all three. The spark plug is where the family stops being a family: Yamaha specifies an NGK LKR6E for the F115 and a different plug for the F90. Buying plugs on the strength of “it is the same engine” is the mistake this catches, and it is worth checking the box against your own model code rather than the family.
Most of the 100-hour service now comes in one box
Yamaha's second-generation 100-hour kit for this family, 6HV-W006B-00-00, holds the oil filter, the engine oil drain plug gasket, the primary fuel filter element and its O-ring, two lower-unit drain plug gaskets and a propeller cotter pin. That is every consumable the service needs apart from the oil itself and the gearcase lube. It also solves the perennial problem with the drain washers, which Yamaha insists are single-use but does not sell under a published part number of their own.
Two jobs on this engine are dealer work, and one has a calendar deadline
Yamaha names valve clearance and timing-belt inspection as procedures to leave to an authorised dealer, and recommends replacing the timing belt every five years or 1000 hours. The five-year half is what catches people out: a lightly used boat can reach it at a few hundred hours, so the calendar arrives long before the hour meter does. Yamaha does not publish a valve-clearance interval on its public pages, so that one comes out of the manual for your serial number.
Manufacturer documentation
The figures above are summarised for quick reference. For the full operator's manual and illustrated parts list, go straight to Yamaha — they keep the current revision, so you always get the right version for your engine.
Yamaha's own maintenance hub. The replacement-schedule chart here uses ● to mean “refer to your Owner's Manual or consult your dealer” — it is not the same as a tick, and several 100-hour rows carry it.
Yamaha's own bulletin for the three second-generation 100-hour kits: what each kit contains and the exact model codes it fits. It is also where Yamaha states the cadence in its own words — every 100 hours or each year, whichever comes first.
The bulletin for the four earlier 100-hour kits, which cover model codes the second-generation kits do not. Worth reading if your clamp-bracket code is missing from the April 2026 list: the first-generation kits hold a different set of parts — impeller, thermostat, anode, trim tab and plugs rather than the oil filter and drain-plug gaskets.
Yamaha serves the manual against your engine's Primary ID (model code, shaft length and serial number), which is on the label on the clamp bracket. Intervals Yamaha does not publish publicly — valve clearance is the one that matters here — are in that manual.
Other engines in this range
Never miss a Yamaha F115 service
Keeply builds your engine's maintenance schedule, tracks the hours, and reminds you before a service is due. Ask First Mate "what's overdue?" and get an answer from your own records. Free to start, no credit card.
Specifications are transcribed from the 115 HP block of Yamaha's own F115 model page (yamahaoutboards.com/outboards/115-30-hp/115-75-hp/f115), read September 14 2026. The oil filter and on-engine fuel filter element part numbers, the 3.4 US qt oil capacity with filter, the spark plug type and the 25.7 / 24.2 fl oz gearcase capacities are from the Capacities & Specifications table on pages 34-35 of Yamaha's Maintenance Matters brochure (© 2024 Yamaha Motor Corporation, U.S.A., hosted on yamahaoutboards.com), read structurally rather than through a summariser. The 100-hour service kit part number, its contents and its model-code fitment list are from Yamaha's 100-Hour Service Kits bulletin dated April 15 2026, also hosted on yamahaoutboards.com. Maintenance intervals are from the pages where Yamaha states them in prose — lower-unit lubricant at 20 then 100 hours, the 50-hour, 100-hour and 300-hour fuel filter intervals, the annual water pump inspection, the five-year / 1000-hour timing belt replacement and the anode replacement threshold. Yamaha publishes no valve-clearance interval publicly and no part numbers for the gearcase lubricant, drain washers, impeller, anodes, trim fluid, timing belt or VST filter; those fields are deliberately empty rather than filled from a retailer. Figures are for reference only — always confirm against the manual for your engine's serial number before ordering parts or carrying out service.