Tohatsu 40HP 4-Stroke Outboard Engine Parts

(22 products)

This page is dedicated to Tohatsu 4‑Stroke 40 HP outboard engines. Use it to find compatible parts and key service information, including maintenance tips, common replacement parts, and practical troubleshooting guidance. You can also browse our main Tohatsu 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 40 HP Model

Find the nameplate/serial label on the transom bracket or swivel bracket; it lists the model code and serial number.
Model code reading: many 4‑stroke 40 HP units use an "MFS40" style code. Suffix letters often denote shaft length (S=short, L=long), control/trim options (E=Electric start, T=Power Trim & Tilt), etc.
4‑Stroke indicators: presence of an engine oil fill cap/dipstick and often an EFI label on the cowl; oil change port on the block.
Record the full model designation and serial number; small suffix changes can affect parts like impellers, anodes, thermostats, and control components.

Engine Overview

Tohatsu 40 HP 4‑Stroke Inline‑3 Platform

Feature	Description
Configuration	Inline‑3, 4‑stroke with electronic fuel injection (EFI); electric start and power trim variants common.
Common Models	Examples include MFS40‑series designations with suffixes for shaft length and options (e.g., S/L/ETL). Verify by serial plate for exact fit.
Advantages	Quiet operation, good fuel economy, solid mid‑range torque, and dependable charging for electronics.
Notes	Many service parts (impellers, anodes, filters) are shared within related 3‑cylinder 4‑stroke families, but confirm by model code and serial. Tohatsu supports these with maintenance and repair kits.

Routine Maintenance & Service Parts

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

Item	Interval*	Remarks	Parts Link
Engine oil + filter	Every 100 hrs or annually (first service ~20 hrs)	Use NMMA FC‑W 10W‑30/40 as specified; warm engine before draining; replace crush washer if applicable.	Oil Filters
Gear oil (lower unit)	Every 100 hrs or annually	Inspect for water intrusion (milky oil). Replace seals if leaks are found.	Tohatsu Lower Unit Seal Kits
Spark plugs	Inspect 100 hrs; replace ~200 hrs or as needed	Check gap and color; replace if fouled or worn.	Spark Plugs
Fuel filter / water separator	Inspect 100 hrs; replace annually or with symptoms	Replace sooner if stale fuel or debris is present; prime system and check for leaks.	Fuel Filters
Water pump impeller / kit	Inspect annually; replace ~200 hrs or 2–3 seasons	Essential for cooling. Replace sooner after overheat events or sandy/muddy use.	Tohatsu Water Pump Repair Kits
Anodes (internal/external)	Check often; replace when ~50% depleted	Use the correct alloy (salt, brackish, or fresh water). Helps protect gearcase and cooling passages.	Anodes
Thermostat	Inspect every 2 seasons; replace if sticking	If overheat or cold‑running symptoms occur, test and replace as needed.	Tohatsu Outboard Parts
Valve clearance check	Typically every 200–300 hrs (model‑specific)	Cold‑engine adjustment per manual; improves idle quality and performance.	Tohatsu Outboard Parts

Frequently Used Parts Categories

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

Common Symptoms & Quick Checks

Symptom	Check First	Related Parts
Weak tell‑tale stream or overheat alarm	Inspect intake screens for debris, verify strong primer bulb, check impeller and thermostat operation; confirm anodes are intact.	Water pump kit, thermostat, intake screen, anodes
Hard starting / rough idle	Use fresh fuel; inspect primer bulb and fuel lines for air leaks; replace fuel filter; check spark plugs; ensure battery voltage for EFI.	Spark plugs, fuel filter, fuel injector, starter circuit components
Poor acceleration / can’t reach WOT	Check propeller for damage or wrong pitch; inspect hull for growth; verify throttle linkage and fuel filter condition.	Propeller, fuel filter, spark plugs
Gearcase noise or metal in gear oil	Drain and inspect oil; check for water intrusion; look for fishing line at prop shaft; evaluate bearing condition.	Lower unit seal kit, bearings, thrust washer

FAQs

Are parts interchangeable between different years or platforms?

Some service items are shared across related Tohatsu inline‑3 4‑stroke models, but changes in model revisions and suffix options can affect fit. Always confirm with your full model code and serial number before ordering.

When should the impeller be replaced?

Inspect yearly and replace about every 2–3 seasons or ~200 hours. Replace sooner after overheating or operation in sandy or silty water.

How often should I change gear oil?

Typically every 100 hours or annually. If you see milky oil (water intrusion) or metal flakes, service the lower unit seals and inspect bearings before further use.

What information helps confirm part compatibility?

Provide the brand (Tohatsu), full model code with suffix, serial number, shaft length, control type (tiller/remote), and photos of the nameplate and the part being replaced.

Ready to find parts by horsepower, year, and model? Browse our main Tohatsu collection to locate compatible components for your 40 HP 4‑stroke.

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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.