Yamaha 4-Stroke 8-15HP Outboard Marine Engine Parts

(3 products)

This page is tailored for Yamaha 4-Stroke 8–15HP outboard engines. Use it to quickly find compatible parts and service information, including maintenance tips, commonly replaced items, and troubleshooting guidance. You can also browse the full Yamaha collection for more options. Scroll to the bottom of this page to start browsing parts for this engine. On the collection page, use the “Filter & Sort” controls to narrow results by horsepower, year range, and part category/section.

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How to Identify Your 8–15HP Model

Nameplate location: Look on the transom bracket or swivel bracket for the Yamaha model/serial plate. This tag shows the model code and serial number required for exact-fit parts.
Reading the model code: For 4-strokes, codes typically begin with “F” (e.g., F8, F9.9, F15). High Thrust versions use “T” (e.g., T9.9). Suffix letters indicate shaft length (S=15", L=20"), control type (H=tiller, R=remote), and a year code letter.
Platform differences: Standard F8/F9.9/F15 models differ from High Thrust T8/T9.9 kickers (larger gear ratio/props). Earlier small 4-strokes are often carbureted; newer variants may be EFI—order fuel/air parts accordingly.
Confirm before ordering: Match horsepower, model code, and year letter to ensure correct gaskets, water pump kits, anodes, and electrical parts.

Platform Overview

Standard 8–15HP (F8 / F9.9 / F15)

Feature	Description
Configuration	Compact inline-2, 4-stroke; carbureted on many earlier models with EFI on some later variants.
Common Models	F8, F9.9, F15 with S (15") or L (20") shafts; H (tiller) or R (remote) controls.
Advantages	Lightweight, easy to service, excellent economy for dinghy, tender, and small fishing rigs.
Notes	Cooling and gearcase parts are shared across close year ranges; fuel/ignition parts can differ by carb vs EFI and by year suffix.

High Thrust Kickers (T8 / T9.9)

Feature	Description
Configuration	Inline-2, 4-stroke tuned for thrust; larger gear ratio and prop selection for heavy boats, trolling, and sailboats.
Common Models	T8, T9.9 in S/L shafts; often with tiller (H) or remote (R) options and model-year suffix letters.
Advantages	Superior low-speed control and pushing power; ideal as a kicker or auxiliary.
Notes	Propellers and some gearcase components differ from standard F models—verify model code when selecting props and seals.

Routine Maintenance & Service Parts

Intervals below are general guidelines for small Yamaha 4-strokes. Always follow the maintenance schedule in your specific service manual.

Item	Interval*	Remarks	Parts Link
Engine oil & filter	Every 100 hours or annually	Use NMMA FC‑W oil; replace filter each oil change.	Oil Filters \| Yamaha Service & Maintenance Kits
Gear oil (lower unit)	Every 100 hours or annually	Change sooner if water intrusion is suspected; inspect magnet for metal.	Yamaha Outboard Parts
Spark plugs	Inspect every 100 hours; replace as needed	Check gap and condition; replace if fouled or worn.	Spark Plugs
Fuel filter / inline filter	Every 100 hours or annually	Replace more often with ethanol fuel or contamination.	Fuel Filters
Water pump impeller / kit	Every 2 seasons (sooner in sandy/silty water)	Key for cooling and overheat prevention.	Yamaha Water Pump Repair Kits
External & internal anodes	Inspect every 50 hours; replace when 50% consumed	Choose alloy for your water (salt, brackish, fresh).	Yamaha Anodes
Gearcase seals (service as needed)	Inspect at each gear oil change	If milky oil is found, pressure/vac test and reseal.	Yamaha Lower Unit Seal Kits

Frequently Used Parts Categories

Routine Service – Yamaha Service & Maintenance Kits
Cooling System – Yamaha Water Pump Repair Kits
Gearcase / Seals – Yamaha Lower Unit Seal Kits
Propulsion – Yamaha Propellers
Corrosion Protection – Yamaha Anodes
Gaskets & Sealing – Yamaha Gaskets
Ignition/Electrical – Yamaha Starters | Spark Plugs

Common Symptoms & Quick Checks

Symptom	Check First	Related Parts
Weak telltale / overheat alarm	Inspect intake screen, thermostat, and impeller condition.	Water pump repair kit, thermostat, intake screen, anodes (internal).
Hard starting / rough idle	Check spark plug condition/gap, stale fuel, and fuel filter.	Spark plugs, inline fuel filter, carb kit (carb models) or injector service (EFI).
Poor acceleration / power loss	Verify prop pitch/condition, compression, and fuel supply.	Propeller, fuel filter, fuel pump, gaskets for air leaks.
Gearcase noise / metal in gear oil	Drain oil and inspect; pressure/vac test for seal failure.	Lower unit seal kit, bearings, shims; fresh gear oil.
Low charging voltage (if equipped)	Check battery health, connections, and rectifier/regulator.	Rectifier/regulator, wiring/connectors, battery terminals.

FAQs

Are parts interchangeable across different years or between F and T models?

Many service items interchange within close year ranges, but High Thrust (T) models often use different props and some gearcase parts. Always confirm by model code and year suffix before ordering.

When should I replace the water pump impeller?

As a preventive measure, replace the impeller every 2 seasons (or sooner in sandy/silty water or heavy use). If the telltale is weak or you have an overheat alarm, service immediately.

How often should I change the gear oil?

Change lower unit gear oil every 100 hours or annually. If the drained oil looks milky, pressure/vac test the gearcase and replace seals before returning to service.

What information helps confirm part compatibility?

Provide the full model code from the nameplate (e.g., F9.9 with shaft/control letters and year suffix), the serial number, and your measured shaft length. Photos of the nameplate and the part needing replacement are also helpful.

Ready to find exact-fit components? Browse the Yamaha collection and narrow by horsepower, year, and model to locate the right parts for your 8–15HP 4-stroke.

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If you’re unsure about your model, send us a photo of the nameplate and the part you need and we’ll help verify compatibility.