Yamaha 4-Stroke 15-90HP Outboard Parts

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This page covers Yamaha 4-Stroke 15–90HP outboard engines and helps you find compatible parts and service information. Below you’ll find maintenance tips, common replacement parts, and troubleshooting guidance specific to this power range. You can also browse the main Yamaha collection for a wider selection. Scroll to the bottom of this page to start browsing parts for this engine, and remember you can use the Filter & Sort controls on the collection page to narrow results by horsepower, year range, and part category.

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How to Identify Your 15–90HP Model

Find the nameplate/serial label on the transom bracket or swivel bracket (usually starboard side). Note the full model code and serial number.
Model code basics: “F” indicates Four Stroke; numbers show horsepower (e.g., F40, F70). S/L/X/U denote shaft length (approx. 15/20/25/30 in). “R” = remote control, “H” = tiller. A trailing letter often indicates the model year.
Platform clues: F15/F20/F25 are small twin-cylinder portables; F40/F50/F60 are common inline‑3 EFI midrange models; F70/F75/F90 are inline‑4 EFI midrange models.
For parts accuracy, always match the exact model suffix (shaft length, controls) and year code from the nameplate.

Platform Overview

Portable 4‑Stroke (F15/F20/F25)

Feature	Description
Configuration	Compact inline‑2 four‑stroke; early models carbureted, many later variants use EFI; manual or electric start.
Common Models	F15, F20, F25 with suffixes for shaft length (S/L) and control type (H/R).
Advantages	Lightweight, portable, excellent fuel economy for tenders, skiffs, and small boats.
Notes	Parts can vary by start method, shaft length, and tiller vs. remote. Verify using full model code.

Midrange Inline‑3 EFI (F40/F50/F60)

Feature	Description
Configuration	Inline‑3 four‑stroke EFI; popular balance of weight, torque, and economy.
Common Models	F40, F50, F60 with typical suffixes for shaft length (S/L/X) and controls (H/R).
Advantages	Strong mid‑range performance, simple maintenance access, broad parts availability.
Notes	EFI systems add filters (e.g., inline and VST). Match parts by exact model and year code.

Midrange Inline‑4 EFI (F70/F75/F90)

Feature	Description
Configuration	Inline‑4 four‑stroke EFI; refined running with good top‑end power.
Common Models	F70, F75, F90 with shaft length options (S/L/X) and remote or tiller controls.
Advantages	Smooth operation, strong acceleration, efficient cruising fuel burn.
Notes	Certain gaskets, anodes, and filters are platform‑specific. Use the full model code to confirm fit.

Routine Maintenance & Service Parts

Intervals below are general guidelines for Yamaha 4‑stroke 15–90HP models. Always follow the official service manual for your exact model and year.

Item	Interval*	Remarks	Parts Link
Engine oil & filter	Every 100 hours or annually	Warm engine, drain completely, replace filter, refill with spec oil.	Yamaha Service & Maintenance Kits
Gear oil (lower unit)	Every 100 hours or annually	Inspect for water intrusion (milky oil) and metal on magnet; replace seals if needed.	Yamaha Lower Unit Seal Kits
Spark plugs	Inspect every 100 hours; replace as needed	Check gap and color; replace on schedule or if fouled/misfiring.	Spark Plugs
Fuel filter (inline/engine)	Every 100 hours or annually	EFI models may also require VST filter service; use fresh fuel and stabilize for storage.	Fuel Filters
Water pump impeller/kit	Every 2 seasons or 200 hours	Replace sooner if tell‑tale weak, overheat alarms, or sand/silt use.	Yamaha Water Pump Repair Kits
Anodes (internal & external)	Inspect each 50 hours; replace when 50% worn	Use the correct alloy for fresh/brackish/salt water to protect aluminum components.	Yamaha Anodes

Frequently Used Parts Categories

Routine Service Kits – Yamaha Service & Maintenance Kits
Cooling System – Yamaha Water Pump Repair Kits
Corrosion Protection – Yamaha Anodes
Fuel System – Fuel Filters
Propellers & Hardware – Yamaha Propellers
Ignition & Starting – Yamaha Starters
Gearcase Seals – Yamaha Lower Unit Seal Kits

Common Symptoms & Quick Checks

Symptom	Check First	Related Parts
Weak tell‑tale or overheat alarm	Inspect intake screens for blockage, check thermostat, and evaluate impeller condition.	Water pump kit, thermostat, intake screen/strainer, anodes
Poor acceleration or loss of power	Check prop condition/pitch, fuel quality, replace fuel filter, inspect plugs and air leaks.	Propeller, fuel filter, spark plugs, fuel hoses/primer bulb
Hard starting or rough idle	Verify battery charge and connections, inspect plugs, check for stale fuel, clean/replace filters.	Spark plugs, fuel filter, starter/battery cables, EFI/VST filter
Gearcase noise or metal in gear oil	Drain and inspect gear oil; look for milky oil (water) or excessive metal; pressure test seals.	Lower unit seal kit, bearings, prop shaft seals, gear oil

FAQs

Are parts interchangeable between different years or platforms?

Some items are shared across families, but many parts differ by platform (inline‑2, inline‑3, inline‑4), shaft length, and control type. Use the full model code: “F” denotes four‑stroke, S/L/X/U indicate shaft length, R/H indicate controls, and a trailing letter commonly indicates the model year.

When should the impeller be replaced?

As a rule of thumb, replace the water pump impeller every 2 seasons or ~200 hours. Replace sooner if the tell‑tale is weak, you hear overheat alarms, or the engine is used in sandy/silty water.

How often should gear oil be changed?

Change the lower unit gear oil every 100 hours or annually. If you see milky oil, metal on the drain plug magnet, or leaks, service the seals and inspect internal components.

What information do you need to confirm part compatibility?

Please provide the full model code (including suffix), serial number, horsepower, approximate year, shaft length, and whether the engine has tiller or remote controls. A clear photo of the nameplate is very helpful.

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