Tohatsu 4-Stroke 75-100HP Marine Engine Parts

(1 products)

This page is for Tohatsu 4‑Stroke 75–100HP outboard engines. Use it to find compatible parts and service information, including maintenance tips, common replacement parts, and troubleshooting guidance. You can also browse the 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.

Browse All Tohatsu Parts

How to Identify Your 75–100HP Model

Locate the model/serial plate on the transom bracket or swivel bracket. Record the full model code and serial number.
Decode the model: examples include MFS75, MFS90, and MFS100 with suffixes that indicate shaft length (S/L/XL), control/steering options, and other variations.
Confirm it’s a 4‑stroke EFI inline‑4 platform: look for the under‑cowl vapor separator and fuel rail, and the coil‑on‑plug ignition layout.
Use the exact model code and serial to verify parts; year alone is not sufficient because updates occur within the same horsepower family.

Engine Overview

Tohatsu 75–100HP 4‑Stroke (Mid‑Range Inline‑4 EFI)

Feature	Description
Configuration	Inline‑4, 4‑stroke EFI outboard with electronic ignition; remote or tiller control depending on model suffix; common L (20") and XL (25") shaft lengths.
Common Models	MFS75, MFS90, MFS100 series (verify complete model code and serial).
Advantages	Good fuel economy and low noise; broad mid‑range torque; straightforward routine service.
Notes	Many routine service parts cross over with related mid‑range models; confirm by model code and serial because gearcase and option changes affect fit.

Routine Maintenance & Service Parts

Intervals below are general guidelines for recreational use. Always follow the schedule and specifications in your official Tohatsu service manual.

Item	Interval*	Remarks	Parts Link
Engine oil + filter	100 hours or annually	Use FC‑W marine oil; confirm viscosity for climate; replace drain plug crush washer if specified.	Oil Filters
Gear oil (lower unit)	100 hours or annually	Inspect for water/milkiness and metal on the drain plug magnet; reseal if contamination is found.	Tohatsu Lower Unit Seal Kits
Spark plugs	Inspect 100 hours; replace ~200 hours or as needed	Verify correct heat range and gap for your model code; torque to spec on a cold engine.	Spark Plug
Fuel filter (inline/under‑cowl)	100 hours or annually	Replace more often with ethanol fuel or dirty tanks; consider adding a water‑separating filter.	Fuel Filters
Water pump impeller/kit	2–3 seasons or ~200 hours	Shorten interval for sandy/silty use or high temps; replace the full kit if wear is present.	Tohatsu Water Pump Repair Kits
Anodes (external & internal)	Inspect every 50 hours; replace at ~50% loss	Match alloy to your water (zinc, aluminum, or magnesium). Keep paint off anode surfaces.	Anodes
Propeller & hub	Inspect every 50 hours; as needed	Check for dings, bent blades, line behind the prop, and hub slippage; grease shaft splines.	Propellers

*Follow the most conservative recommendation between hours and calendar time, and adjust for severe service or commercial use.

Frequently Used Parts Categories

Routine Service Kits – Service & Maintenance Kits
Cooling System – Tohatsu Water Pump Repair Kits
Fuel System – Fuel Filters
Ignition / Spark – Spark Plug
Lower Unit Sealing – Tohatsu Lower Unit Seal Kits
Propulsion – Propellers
Corrosion Protection – Anodes

Common Symptoms & Quick Checks

Symptom	Check First	Related Parts
Weak telltale stream or overheat alarm	Clear intake screens; verify impeller age/condition; test thermostat operation.	Water pump kit, thermostat, intake screen cleaning
Hard starting or rough idle	Check battery voltage and connections; inspect/replace spark plugs; confirm clean fuel and filter.	Spark plugs, fuel filter, electrical connectors
Poor acceleration or power loss	Inspect propeller for damage or hub slip; check for water in fuel; verify throttle/shift cable adjustment.	Propeller/hub, fuel filter, control cables
Gearcase noise or metal in gear oil	Check oil level and condition; look for fishing line on the prop shaft; pressure test if water intrusion is suspected.	Lower unit seal kit, bearings, shims (as required)

FAQs

Are parts interchangeable across different years or related platforms?

Many routine service items are shared within the mid‑range family, but differences by year, gearcase, and options mean interchangeability is not guaranteed. Always verify with the exact model code and serial.

When should I replace the water pump impeller?

Typically every 2–3 seasons or about 200 hours. Shorten the interval for sandy or silty water, high operating temperatures, or if the telltale weakens or overheating occurs.

How often should the lower unit gear oil be changed?

Change at 100 hours or annually. Inspect drained oil for milkiness (water) and metal on the magnetic plug; address sealing issues if contamination is present.

What information helps confirm part compatibility?

Provide the full model code, serial number, shaft length, control type (remote or tiller), and photos of the existing part whenever possible.

Ready to find parts by horsepower, year, and model? Browse the main Tohatsu collection and use “Filter & Sort” to dial in your 75–100HP 4‑stroke.

Shop Tohatsu Outboard Parts

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.