Parsun 20HP 2-Stroke Outboard Marine Engine

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This page focuses on Parsun 2‑Stroke 20HP outboard engines. It helps you identify compatible parts and provides service guidance, including maintenance tips, commonly replaced items, and troubleshooting checks. You can also browse our main parts categories if a dedicated Parsun collection isn’t available. Scroll to the bottom of this page to start browsing parts for this engine, and remember you can use the collection page “Filter & Sort” tools to narrow results by horsepower, year range, and part category.

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How to Identify Your 20HP Model

Find the nameplate/serial plate on the transom bracket or swivel bracket; it lists the model designation and serial number.
Read the model code and suffix: letters often indicate shaft length (S=15 in, L=20 in), control type (tiller vs. remote), and starting method (manual vs. electric).
Confirm it is a 2‑stroke model (premix or oil‑injection) rather than a 4‑stroke; this affects ignition, fuel, and cooling parts.
Note key options that influence parts: short vs. long shaft, tiller vs. remote, and manual vs. electric start.

Platform Overview

Parsun 20HP 2‑Stroke (Inline‑2, Carbureted)

Feature	Description
Configuration	Inline‑2, carbureted 2‑stroke; CDI ignition, through‑hub exhaust
Common Models	20HP 2‑stroke variants with 15 in (short) or 20 in (long) shaft; tiller or remote; manual or electric start
Advantages	Lightweight and simple; strong low‑to‑midrange torque; easy trailer/portable use
Notes	Propeller pitch selection, shaft length, and control type affect parts compatibility. Maintain the cooling pump and gearcase annually.

Routine Maintenance & Service Parts

Intervals below are general guidelines for small 2‑stroke outboards. Always follow the procedures and schedules in your official service manual.

Item	Interval*	Remarks	Parts Link
Gear oil (lower unit)	Every 100 hrs or annually	Use marine SAE 90 gear lube; inspect for water/milkiness and metal debris	Lower Unit Seal Kits
Spark plugs	Inspect 50 hrs; replace 100 hrs/season	Check heat range and gap; replace if fouled or worn	Spark Plugs
Fuel filter / inline filter	Inspect 50 hrs; replace as needed	Drain/replace if contaminated; keep water separators serviced	Fuel Filters
Water pump impeller / kit	Inspect annually; replace 1–2 years	Essential for cooling; replace sooner if overheat/weak tell‑tale	Water Pump Impeller Rebuild Kits
Anodes (sacrificial)	Inspect 50 hrs; replace at ≤50% remaining	Use correct alloy for your water (zinc, aluminum, or magnesium)	Anodes
2‑stroke oil & fuel mix	Every fill‑up (premix) or per system checks	Use TC‑W3 marine oil at the ratio specified by your manual (often 50:1 for premix). For oil‑injection models, service lines and pump per manual.	Service & Maintenance Kits

Frequently Used Parts Categories

Routine Service – Service & Maintenance Kits
Cooling System – Water Pump Impeller Rebuild Kits
Fuel System – Fuel Filters
Fuel Delivery – Fuel Pumps
Ignition / Electrical – Electrical Items
Propellers & Hardware – Propellers
Lower Unit & Seals – Lower Unit Seal Kits

Common Symptoms & Quick Checks

Symptom	Check First	Related Parts
Weak tell‑tale or overheat alarm	Inspect intake screens for blockage, thermostat operation, and impeller condition	Water pump kit, thermostat, intake screen, gaskets
Poor acceleration / power loss	Check prop damage/pitch, fuel quality, fuel filter, and spark plugs; verify compression if persistent	Propeller, fuel filter, spark plugs, carburetor repair kit
Hard starting / rough idle	Confirm choke/enrichment operation, correct plug gap, fresh fuel, and no air leaks in fuel line/bulb	Spark plugs, fuel filter, fuel hoses/primer bulb, carburetor repair kit
Excessive smoke (2‑stroke)	Verify oil mix ratio, ensure choke isn’t left on, and set idle mixture per manual	Spark plugs, fuel, fuel/oil hoses
Gearcase noise / metal in oil	Check gear lube level/condition; inspect for water intrusion and prop‑shaft seal damage	Lower unit seal kit, drain/fill seals, prop‑shaft seal, gear lube

FAQs

Are parts interchangeable between different years or between 2‑stroke and 4‑stroke 20HP models?

Not reliably. Even within 20HP models, changes in platform (2‑stroke vs. 4‑stroke), shaft length, ignition, and control options can affect fit. Verify using the exact model code, serial number, and configuration details.

When should I replace the water pump impeller?

Inspect annually and replace every 1–2 seasons or 100 hours. Replace immediately if you see a weak tell‑tale, overheating, or after running aground or through debris.

How often should I change the lower unit gear oil?

Every 100 hours or at least once per season. If the oil looks milky, smells burnt, or contains metal, service the seals and address any internal issues before further use.

What information helps confirm part compatibility?

Provide a clear photo of the nameplate, the full model code and serial number, shaft length (15 in or 20 in), control type (tiller or remote), start type (manual or electric), and the existing part number if known.

Ready to find parts by category? Browse our most‑requested outboard parts and use the collection page filters to narrow by horsepower, model, and part type.

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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.