Yamaha 2-Stroke 100HP Outboard Engine Parts

(41 products)

This page is dedicated to Yamaha 2-Stroke 100HP outboard engines. Use it to find compatible parts and practical 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 selection of components. Scroll to the bottom to start browsing parts for this engine, and remember that on the collection page you can use the Filter & Sort controls to narrow results by horsepower, year range, and part category/section.

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How to Identify Your 100HP Model

Locate the nameplate/serial plate on the transom bracket or swivel bracket. It lists the model code, serial number, and sometimes the shaft length.
Read the model code and suffix: letters typically denote start type, trim/tilt, shaft length (S/L/XL), and market year. Bring the full code when confirming parts.
This page covers 2-stroke variants. Do not confuse them with Yamaha F100 4-stroke models (codes beginning with “F”), which use different service parts.
Oil-injected 2-strokes have a remote or under-cowl oil tank; premix models require the correct fuel/oil ratio. Check your owner’s label for the specification.

Engine Overview

Yamaha 100HP 2-Stroke (Typical Configuration)

Feature	Description
Configuration	Carbureted 2-stroke outboard, commonly oil-injected; platform varies by market and year.
Common Models	100HP 2-stroke models with suffixes indicating shaft length and trim/tilt. Not to be confused with F100 (4-stroke) variants.
Advantages	Relatively light weight for the output, strong hole-shot, straightforward maintenance.
Notes	Certain parts interchange with other Yamaha families in specific years. Verify by model code and serial number for best fit.

Routine Maintenance & Service Parts

Intervals below are general guidelines for 2-stroke outboards. Always follow the maintenance schedule in your official Yamaha service manual.

Item	Interval*	Remarks	Parts Link
Gear oil (lower unit)	Every 100 hours or annually	Inspect for water intrusion and metal shavings; replace drain/fill gaskets.	Yamaha Lower Unit Seal Kits
Spark plugs	Every 100 hours or annually	Use the correct heat range and gap; replace if fouled or worn.	Spark Plugs
Fuel filter / water-separating filter	Inspect often; replace 100–200 hours	Critical for ethanol fuels; replace sooner if contamination is present.	Fuel Filters
Water pump impeller/kit	Every 2–3 seasons (or 200–300 hours)	Replace sooner if weak telltale, overheat alarms, or debris ingestion.	Yamaha Water Pump Repair Kits
Anodes (zincs)	Inspect every trip; replace when 50% consumed	Choose alloy for your water (zinc, aluminum, magnesium).	Yamaha Anodes
Fuel/oil mix or oil injection system	Check every service	Verify correct premix ratio or test oil pump operation; inspect and replace brittle hoses.	Hoses

*Intervals are general recommendations and may vary by operating conditions. Always consult your Yamaha service manual.

Frequently Used Parts Categories

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

Common Symptoms & Quick Checks

Symptom	Check First	Related Parts
Weak telltale or overheat alarm	Inspect intake screens, thermostat, and water pump impeller; ensure hose is not kinked.	Water pump kit, intake screen, thermostat, gaskets
Poor acceleration or power loss	Check prop pitch/damage, fuel filter restriction, plug condition, and carb synchronization.	Propeller, fuel filter, spark plugs, gasket sets
Hard starting / rough idle	Verify fresh fuel, no air leaks in lines, clean carbs, and proper spark plug gap.	Fuel hoses, fuel filter, carb gaskets, spark plugs
Excessive smoke (2-stroke)	Confirm correct premix ratio or oil pump calibration; look for stuck choke/enrichment.	Hoses, gaskets, spark plugs
Gearcase noise or metal in gear oil	Change gear oil and inspect for water; pressure/vacuum test the case and seals.	Lower unit seal kit, drain/fill gaskets, bearings (as applicable)

FAQs

Are parts interchangeable between different years or platforms?

Some items interchange across Yamaha 2-stroke families and years, but many do not. Always verify with your exact model code and serial number. 2-stroke 100HP parts are generally not interchangeable with F100 (4-stroke) components.

When should I replace the water pump impeller?

As a preventive measure every 2–3 seasons (200–300 hours), or immediately if cooling flow is weak, the engine overheats, or the impeller shows signs of hardening or cracking.

How often should I change gear oil?

At least every 100 hours or annually. Inspect the drained oil for milky color (water) or excessive metal. Replace drain/fill gaskets at each service.

What information helps confirm part compatibility?

Provide the full model code, serial number, shaft length, and any visible part numbers. Photos of the nameplate and the part being replaced are very helpful.

Ready to find parts? Browse the main Yamaha collection to filter by horsepower, year, and model for the best match to your 100HP 2-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.