Tohatsu 40HP 2-Stroke Outboard Marine Engine Parts

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This page focuses on Tohatsu 2‑Stroke 40HP outboard engines and helps you find compatible parts and service information. Below you’ll find maintenance tips, common replacement parts, and troubleshooting guidance. You can also browse the main Tohatsu parts collection. Scroll to the bottom to start browsing parts for this engine, and remember you can use the “Filter & Sort” controls on the collection page to narrow by horsepower, year range, and part category.

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How to Identify Your 40HP Model

Locate the identification/serial plate on the transom clamp or swivel bracket. Record the full model code and serial number.
Decode suffixes to confirm features: examples include M (manual start), E (electric start), F (tiller), P (remote control), T (power trim & tilt), O (oil auto‑mix). Shaft length is typically S = 15 in, L = 20 in.
2‑Stroke variants may be pre‑mix (fuel/oil mixed in tank) or auto‑mix (separate oil tank and oil pump). Auto‑mix models usually have an oil tank, filler cap under the cowl, and an oil filter in the system.
Platform cues: the 40HP D2‑series is an inline‑3, carbureted 2‑stroke with through‑hub exhaust; electric‑start versions add a 12V charging alternator.

Engine Overview

Tohatsu 40HP 2‑Stroke D2‑Series

Feature	Description
Configuration	Inline‑3, carbureted 2‑stroke; through‑hub exhaust; lubrication by pre‑mix (typ. 50:1; richer during break‑in) or auto‑mix oil injection depending on variant.
Common Models (examples)	M40D2 MF (manual/tiller), M40D2 EPO (electric, remote, oil autolube), M40D2 EPTO (electric, remote, PTT, oil autolube), M40D2 EFTO (electric, tiller, PTT/gas assist). Naming varies by market.
Advantages	Light weight, simple maintenance, strong holeshot and mid‑range torque; broad propeller availability for different loads.
Notes	Verify WOT RPM with your prop (target range typically around 5000–5700). Many lower‑unit and hardware items are shared across the D2 family; always confirm by model code, shaft length, and control/tilt options.

Routine Maintenance & Service Parts

Intervals below are general guidelines for typical recreational use. Always follow the procedures and schedules in your official owner’s/service manual.

Item	Interval*	Remarks	Parts Link
Lower Unit Gear Oil	Every 100 hours or annually	Use marine GL‑5 SAE 80–90; inspect for water/milkiness. Replace drain plug gaskets when needed.	Tohatsu Outboard Parts
Spark Plugs	Inspect 50 hrs; replace 100–200 hrs	Clean/inspect and set gap (approx. 0.9–1.0 mm). Use the correct NGK heat range specified for your model.	Spark Plugs
Fuel Filter(s)	Inspect 50 hrs; replace as needed	Drain water/debris and replace clogged elements to protect carburetors.	Fuel Filters
Water Pump Impeller / Kit	200 hrs or 1–2 seasons (annually in sandy/silty water)	Restores cooling flow and protects against overheating.	Tohatsu Water Pump Repair Kits
Anodes (Corrosion Protection)	Check every 3 months; replace when ~50% depleted	Do not paint or grease. Critical for salt/brackish water use.	Anodes
Oil Injection Filter & Hoses (auto‑mix models)	Inspect annually	Check for leaks, replace clogged filter, and purge air per manual.	Oil Filters
Propeller & Hardware	Inspect each trip; torque/replace cotter during service	Check for bent blades/cavitation; verify WOT RPM falls in spec with your load.	Propellers
Lower Unit Seals (if water found in oil)	As needed	Reseal if pressure/vacuum tests fail or gear oil shows water intrusion.	Tohatsu Lower Unit Seal Kits

*Intervals are typical for recreational use; adjust for heavy, commercial, or harsh‑water operation.

Frequently Used Parts Categories

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

Common Symptoms & Quick Checks

Symptom	Check First	Related Parts
Weak tell‑tale stream / overheat alarm	Inspect intake screens for debris, verify impeller condition, check for pinched hoses; confirm thermostat function.	Water pump kit, intake screens, thermostat, anodes
Poor acceleration or power loss	Check prop damage/cavitation, fuel filter restriction, primer bulb firmness, and spark plug condition/gap.	Propeller, fuel filter, spark plugs, fuel line/primer bulb
Hard starting / rough idle	Confirm choke operation, look for air leaks at connectors, verify fresh fuel and correct 2‑stroke oiling (pre‑mix or auto‑mix), check plug gap.	Spark plugs, fuel filter, carburetor service parts, oil injection filter
Excessive smoke (2‑Stroke)	Verify fuel/oil ratio (pre‑mix) or oil pump setting (auto‑mix); ensure choke isn’t stuck partially on.	Spark plugs, choke components, oil injection components
Gearcase noise or metal in gear oil	Check for fishing line on prop shaft, inspect prop thrust washer and nut torque; pressure/vacuum test lower unit.	Lower unit seal kit, prop hardware, gear oil

FAQs

Are parts interchangeable between different years or between 40HP and other D2 models?

Many fasteners and gearcase components are shared within the D2 family, but ignition, carburetion, control, and oil‑injection parts can vary by model code, shaft length, and options (manual vs. electric start, tiller vs. remote, power trim & tilt). Match by full model code and serial number to be sure.

When should I replace the impeller?

As a preventative measure, replace the impeller every 200 hours or every 1–2 seasons (annually if you operate in sandy/silty or weedy water), or immediately if tell‑tale flow weakens or an overheat alarm occurs.

How often should lower unit gear oil be changed?

Typically every 100 hours or at least once per season. Inspect the drained oil; milky color indicates water intrusion and the need for seal inspection/replacement.

What information do you need to confirm part compatibility?

Please provide the full model code, serial number, shaft length (S/L), start type (manual/electric), control type (tiller/remote), and whether the engine is pre‑mix or oil‑injection. A photo of the nameplate helps us verify quickly.

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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.