Tohatsu 3.5HP 2-Stroke Outboard Engine Parts

(7 products)

This page is dedicated to Tohatsu 2‑Stroke 3.5HP outboard engines. Use it to find compatible parts and service information, including maintenance tips, common replacement items, and troubleshooting guidance. You can also browse our main Tohatsu Outboard Parts collection. Scroll to the bottom of this page to start browsing parts for this engine, and 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 3.5HP Model

Locate the nameplate/serial plate on the transom clamp bracket (often starboard side). Record the full model designation and serial number.
Model coding: look for "M3.5" plus a suffix that can indicate shaft length (S = short, L = long) and other options. The suffix and serial range help ensure parts compatibility.
Platform cues: these small 2‑stroke models are typically single‑cylinder, carbureted, pull‑start tiller units. If you have a 4‑stroke or EFI, you are on a different platform.
If parts differ by year: note the serial number range stamped on the plate; many wear items carry across years, but gaskets, seals, and ignition components can change with updates.

Engine Overview

Tohatsu 3.5HP 2‑Stroke (Small Portable Class)

Feature	Description
Configuration	Single‑cylinder, carbureted 2‑stroke; manual start; tiller steer; lightweight portable design.
Common Models	M3.5 2‑Stroke variants in short (S) and long (L) shaft lengths; model suffix and serial range determine exact parts.
Advantages	Very light and easy to handle; simple maintenance; good low‑speed maneuverability for tenders and small boats.
Notes	Wear items like impellers, spark plugs, and many gaskets are common across years. Always confirm by model code and serial number; some parts can vary with minor production updates.

Routine Maintenance & Service Parts

Intervals below are general guidelines for typical use. Always follow the official Tohatsu service manual for your exact model and operating conditions.

Item	Interval*	Remarks	Parts Link
Lower unit gear oil	Every 100 hours or annually	Check for water intrusion (milky oil) and metal on the magnet; replace gaskets with each service.	Service & Maintenance Kits
Spark plugs	Inspect 50 hours; replace 100 hours or as needed	Use the correct heat range and gap per the manual; carry a spare plug onboard.	Spark plug
Inline fuel filter	Inspect 50 hours; replace 100 hours or if contaminated	Replace if flow is restricted or debris is visible; keep fuel fresh.	Fuel Filters
Water pump impeller / kit	200 hours or every 2 seasons (sooner in sandy/silty water)	Essential for cooling; replace immediately if telltale stream is weak or intermittent.	Tohatsu Water Pump Repair Kits
Anodes (sacrificial)	Inspect every 50 hours; replace when 50–60% consumed	Use the correct material for your water (zinc, aluminum, or magnesium).	Anodes
Lower unit seal kit	As needed (signs of leaks or milky gear oil)	Replace prop shaft and driveshaft seals if water intrusion is present; pressure/vacuum test after service.	Tohatsu Lower Unit Seal Kits
Carburetor service	As needed (storage, varnish, rough idle)	Clean jets and passages; replace soft gaskets; synchronize idle mixture per manual.	Carburetor
Fuel/oil mix (2‑Stroke)	At every refuel	Use fresh gasoline and marine TC‑W3 2‑stroke oil at the ratio specified by your manual (commonly 50:1 on small Tohatsu). Mix thoroughly.	Tohatsu Outboard Parts

Frequently Used Parts Categories

Routine Service: Service & Maintenance Kits
Cooling System: Tohatsu Water Pump Repair Kits
Fuel System: Fuel Filters
Ignition / Electrical: Electrical Items
Gearcase & Seals: Tohatsu Lower Unit Seal Kits
Propellers: Propellers
Corrosion Protection: Anodes

Common Symptoms & Quick Checks

Symptom	Check First	Related Parts
Weak telltale stream / overheat alarm	Inspect intake screens for blockage; verify impeller condition; confirm thermostat is operating.	Water pump repair kit, intake screen, thermostat
Poor acceleration / power loss	Check for fouled propeller, dirty carb jets, restricted fuel filter, and worn spark plug.	Propeller, carburetor kit, fuel filter, spark plug
Hard starting / rough idle	Use fresh fuel; verify choke operation; set idle mixture per manual; check plug gap; look for air leaks on fuel lines.	Spark plug, carburetor gaskets/jets, fuel hoses/clamps
Excessive smoke (2‑stroke)	Confirm correct fuel/oil ratio; ensure warm‑up; inspect plug heat range and condition.	Spark plugs, fresh fuel, correct TC‑W3 oil
Gearcase noise / metal in oil	Drain oil and inspect; check for water (milky oil); inspect prop shaft for fishing line cutting seals.	Lower unit seal kit, gear oil, bearings

FAQs

Are parts interchangeable between different years of the 3.5HP 2‑stroke?

Many routine service parts (impellers, spark plugs, some gaskets) are shared across multiple years. However, ignition, carburetion, and seal dimensions may change with updates. Always confirm using your exact model suffix and serial number.

When should I replace the impeller?

As a preventive service, replace the impeller every 200 hours or every two seasons—sooner if operating in sandy, silty, or shallow debris‑prone water, or if the telltale stream weakens.

How often should the gear oil be changed?

Replace lower unit gear oil every 100 hours or annually. Inspect for signs of water intrusion (milky color) or metal on the drain plug magnet and address seal issues promptly.

What information do you need to confirm part compatibility?

Please provide the full model code (including suffix), serial number, shaft length (S or L), and a photo of the nameplate and the part you’re replacing. This ensures we match the correct components the first time.

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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.