Yamaha 2-Stroke Outboard Engine Parts (4-350HP)

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This page covers Yamaha 2‑Stroke 4–350HP outboard engines and helps you quickly find compatible parts and service information. Below you’ll find maintenance tips, common replacement parts, and troubleshooting guidance. You can also browse the main Yamaha collection for a wider parts selection. Scroll to the bottom of this page to start browsing parts for this engine, and when you land on the collection, use the Filter & Sort controls to narrow results by horsepower, year range, and part category.

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How to Identify Your 2‑Stroke 4–350HP Model

Locate the nameplate/serial sticker on the transom or swivel bracket. It lists the model code, serial number, and horsepower rating.
Read the model code and suffix: letters typically indicate shaft length (S/L/XL), control type (tiller vs. remote), and sometimes production revision or year code. Suffix changes can affect parts compatibility.
Confirm oiling type: many Yamaha 2‑strokes are oil‑injected with a remote tank and small inline oil filter; others are pre‑mix. The oiling system type influences maintenance items.
Note platform cues: compact portables (small cowling, 1–2 cyl), mid‑range (often inline platforms), and larger high‑output models (bigger gearcases and cowlings). Platform differences can change impeller size, ignition components, and fuel system parts.

Platform Overview

Portable 2‑Stroke (Approx. 4–15HP)

Feature	Description
Configuration	Lightweight 2‑stroke portable platforms (single or twin‑cylinder, carbureted).
Common Models	Small 4–15HP 2‑stroke variants used on tenders, inflatables, and small skiffs.
Advantages	Very light, easy to service, strong low‑end thrust for size.
Notes	Check shaft length (S/L). Impellers, spark plugs, and carb settings are platform‑specific; verify with model code.

Mid‑Range 2‑Stroke (Approx. 20–90HP)

Feature	Description
Configuration	Inline carbureted 2‑stroke platforms; many are oil‑injected with remote tanks and inline oil filters.
Common Models	Popular 40–90HP classes for bay boats, jons, and light center consoles.
Advantages	Good power‑to‑weight, simple fuel systems, responsive mid‑range torque.
Notes	Carb jetting/links and gearcase sizes vary by HP and year; match parts to the exact model suffix.

High‑Output 2‑Stroke (Approx. 115–300HP)

Feature	Description
Configuration	Larger 2‑stroke platforms including carb/EFI and high‑pressure direct injection (HPDI) variants.
Common Models	Offshore‑capable 115–300HP classes for heavier hulls and multi‑species fishing.
Advantages	High power density with strong top‑end; HPDI improves fuel economy and emissions vs. carb setups.
Notes	HPDI fuel pumps and filters are unique to that system. Gearcase, water pump, and ignition parts differ by year/HP—confirm with the model code and suffix.

Routine Maintenance & Service Parts

Intervals below are general guidelines for Yamaha 2‑stroke outboards. Always follow the official service manual for your exact model and usage conditions.

Item	Interval*	Remarks	Parts Link
Gear oil (lower unit)	Every 100 hours or annually	Inspect for water (milky oil) or metal; reseal if contamination is present.	Yamaha Lower Unit Seal Kits
Spark plugs	Inspect every 50 hours; replace ~100 hours	Check heat range and gap per model; fouling indicates fuel or oiling issues.	Spark Plugs
Fuel filter / water separator (inline or under‑cowl)	Every 100 hours or annually	Replace more often with ethanol fuel or dirty tanks; prime system after service.	Fuel Filters
Water pump impeller / kit	Every 2 years or 200 hours (yearly in sandy/silty water)	Weak telltale or overheat alarm often indicates wear; inspect housing and key.	Yamaha Water Pump Repair Kits
Anodes (internal & external)	Inspect each service; replace at ~50% depletion	Match alloy to water type (salt/brackish/fresh) and keep mounting points clean.	Yamaha Anodes
2‑stroke oil system service (oil‑injected models)	Seasonally or every 100 hours	Inspect/replace small inline oil filter, check remote tank, lines, and prime pump.	Yamaha Service & Maintenance Kits
Fuel/oil mix (pre‑mix models)	Each refuel	Use the ratio specified in your manual (commonly 50:1 with TC‑W3 oil) and fresh gasoline.	Yamaha Outboard Parts

Frequently Used Parts Categories

Routine Service – Yamaha Service & Maintenance Kits
Cooling System – Yamaha Water Pump Repair Kits
Fuel System – Fuel Filters
Ignition / Electrical – Yamaha Starters
Propulsion – Yamaha Propellers
Gearcase / Sealing – Yamaha Lower Unit Seal Kits
Corrosion Protection – Yamaha Anodes

Common Symptoms & Quick Checks

Symptom	Check First	Related Parts
Weak telltale or overheat alarm	Inspect intake screens for debris; verify impeller and housing; check thermostat operation.	Water pump kit, intake screen, thermostat, anodes
Poor acceleration or power loss	Confirm clean fuel and proper venting; replace fuel filter; inspect plugs; check prop condition/pitch.	Fuel filters, spark plugs, carburetor components, propeller
Hard starting or rough idle	Prime bulb and check for air leaks; verify choke/enricher; clean carbs; inspect plug gap/condition.	Fuel hose/primer, carb kits, spark plugs
Excessive smoke (2‑stroke)	Verify oil injection setting or pre‑mix ratio; ensure choke isn’t sticking; use fresh fuel/oil.	Hoses, oil system filter, spark plugs
Gearcase noise or metal in gear oil	Drain and inspect oil; check for water intrusion; evaluate shaft seals and bearing condition.	Lower unit seal kit, bearings, gear lube

FAQs

Are parts interchangeable between different years or platforms?

Some common service items may cross over, but many components differ by horsepower, platform, and model suffix. Always match parts to the exact model code and serial range for best results.

When should I replace the impeller?

As a rule, every 2 years or ~200 hours, and yearly if you run sandy or shallow water. Replace sooner if you see weak telltale flow or any overheat condition.

How often should I change the gear oil?

Change at least annually or every 100 hours. If the engine has been submerged or you find milky oil or metal, service immediately and inspect seals and bearings.

What information do you need to confirm part compatibility?

Provide the full model code and suffix from the nameplate, serial number, shaft length, control type (tiller/remote), and a brief description of the symptom or service being performed.

Ready to find the right parts? Browse the main Yamaha collection by horsepower, year, and model.

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