Tohatsu 4-Stroke 4-6HP Outboard Marine Engine Parts

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This page is dedicated to Tohatsu 4-Stroke 4-6HP outboard engines and helps you find compatible parts and practical service information. Below you9ll find maintenance tips, common replacement parts, and quick troubleshooting guidance. You can also browse our main Tohatsu collection at any time. Scroll to the bottom of this page 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.

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How to Identify Your 4-6HP Model

Nameplate location: Check the identification/serial plate on the transom bracket (typically port side) and the engine block sticker.
Decoding the model code: The prefix generally indicates a 4-stroke portable model and horsepower; suffixes denote shaft length (short/long), tiller vs remote control, and manual vs electric start/charging options.
Shared platform: Many 4HP, 5HP, and 6HP models share the same core platform with differences in carburetion and propeller pitch, so numerous service parts interchange.
Year vs model code: The printed production date on emissions labels may not equal the marketed model year0verify by full model code and serial.

Engine Overview

Portable 46HP 4-Stroke Platform

Feature	Description
Configuration	Single-cylinder, carbureted 4-stroke, water-cooled portable outboard.
Common Models	4HP, 5HP, 6HP portable 4-stroke outboards (examples include MFS4/MFS5/MFS6 families; tiller or remote variants).
Advantages	Lightweight and easy to transport, very economical fuel use, simple routine service. Some versions offer 12V charging.
Notes	Many wear items (impeller, plugs, anodes, gearcase seals) are common across 4/5/6HP. Verify shaft length and starting/charging options before ordering. Propeller pitch varies by load and application.

Routine Maintenance & Service Parts

Intervals below are general guidelines for small 4-stroke portables; always follow the official service manual for your exact model and operating conditions.

Item	Interval*	Remarks	Parts Link
Engine oil (+ filter if equipped)	Every 100 hours or annually	Use the viscosity grade specified by the manual. Replace the oil filter only if your variant uses one.	Oil Filters
Gear oil (lower unit)	Every 100 hours or annually	Inspect for water intrusion (milky oil). Replace seals if contamination is found.	Tohatsu Lower Unit Seal Kits
Spark plugs	Inspect every 50 hours; replace at 100 hours or annually	Check gap and insulator condition. Replace if fouled or worn.	Spark Plugs
Fuel filter (inline)	Inspect every 50 hours; replace at 100 hours or as needed	Replace sooner if stale fuel or debris is suspected. Ensure proper fuel tank venting.	Fuel Filters
Water pump impeller/kit	Every 200 hours or 22 seasons	Critical for cooling. Replace sooner if weak telltale or overheat conditions occur.	Tohatsu Water Pump Repair Kits
Anodes (sacrificial)	Inspect every 50 hours; replace when 50% consumed	Choose material (aluminum/zinc/magnesium) for your water type. Keep paint off anodes.	Anodes

Frequently Used Parts Categories

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

Common Symptoms & Quick Checks

Symptom	Check First	Related Parts
Weak telltale stream or overheat alarm	Inspect intake screens for blockage; verify strong primer bulb; check impeller age and thermostat operation.	Water pump kit, thermostat, intake screen
Hard starting or rough idle	Confirm fresh fuel and proper tank venting; set choke/enrichment correctly; inspect plug gap and condition; check idle mixture and air leaks.	Spark plugs, fuel filter, carburetor kit
Poor acceleration or power loss	Examine propeller for damage/cavitation; verify throttle linkage travel; check for clogged fuel filter or fouled plug.	Propeller, fuel filter, spark plugs
Gearcase noise or milky gear oil	Drain and inspect gear oil for water; pressure/vacuum test; check propshaft and driveshaft seals.	Lower unit seal kit, bearings, gear lube
No battery charging (if equipped)	Verify charging coil option is installed; check rectifier/regulator connectors and fuses; measure AC stator and DC output.	Rectifier/regulator, wiring connectors, fuse

FAQs

Are parts interchangeable between 4HP, 5HP, and 6HP models?

Many service items are shared across these portables because they use a common platform. However, verify by full model code and serial numberespecially for propellers, jetting, and electrical/charging options.

When should I replace the water pump impeller?

As preventive maintenance, replace the impeller every 22 seasons or about 200 hours. In sandy or silty water, inspect and replace more frequently, and anytime the telltale weakens or the engine overheats.

How often should I change the lower unit gear oil?

Change gear oil every 100 hours or annually, and immediately after any suspected impact or water intrusion. Milky or foamy oil indicates waterinspect and reseal the gearcase before continued use.

What information helps confirm part compatibility?

Please provide the full model code, serial number, shaft length (short/long), tiller or remote control, and whether the engine has electric start/charging. Photos of the nameplate and the part youa looking to replace are very helpful.

Ready to find parts by horsepower, year, and model? Browse our main Tohatsu collection and use the Filter & Sort tools to narrow down to your exact 46HP setup.

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If youre unsure about your model, send us a clear photo of the nameplate and the part you need and well help verify compatibility.