Tohatsu 4-Stroke 8-9.8HP Outboard Marine Engine Parts

(3 products)

This page supports Tohatsu 4-Stroke 8–9.8HP outboard engines and helps you find compatible parts and practical service information. Inside you’ll find maintenance intervals, commonly replaced parts, and troubleshooting guidance. You can also browse the main Tohatsu collection. Tip: 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.

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How to Identify Your 8–9.8HP Model

Find the identification plate on the transom bracket (usually starboard side). It lists the model (e.g., MFS8 or MFS9.8) and the serial number.
Read the model code: “MFS” denotes a 4-stroke; the number is horsepower. Suffix letters typically indicate shaft length (S/L), start type (manual/electric), and control style (tiller vs remote such as EP/EPT).
8HP and 9.8HP are sister portable platforms. Many service parts interchange, but rigging parts (remote vs tiller), props, and some anodes/trim-tabs may differ.
Record the full model and serial. Certain corrosion-protection anodes are mounted inside the water passages and trim tab; part style can vary by serial range.

Engine Overview

Portable Twin-Cylinder Platform (MFS8 / MFS9.8)

Feature	Description
Configuration	Inline-2, carbureted 4-stroke with CDI ignition; manual or electric start; tiller or remote control options.
Common Models	MFS8 and MFS9.8 in S/L shaft lengths; tiller and remote (EP/EPT) variants.
Advantages	Lightweight and portable, quiet operation, low fuel consumption, strong low‑to‑midrange torque for tenders and small boats.
Notes	Many wear items are shared across 8–9.8HP models. Anodes may be located inside the water passages and at the trim tab. Remote-control versions use different rigging/steering parts than tiller models—verify before ordering.

Routine Maintenance & Service Parts

Intervals below are common guidelines for portable 4-strokes. Always consult your specific service manual for the final schedule and torque specs.

Item	Interval*	Remarks	Parts Link
Engine oil & filter	Every 100 hours or annually	Use marine 4-stroke oil; replace the filter and crush washer; check for fuel dilution.	Oil Filters
Gear oil (lower unit)	Every 100 hours or annually	Inspect for water (milky) or metal. Replace seals if contamination is found.	Tohatsu Lower Unit Seal Kits
Spark plugs	Inspect at 100 hours; replace as needed	Check gap and color. Replace if fouled, worn, or at scheduled interval.	Spark Plugs
Fuel filter / water separator	Every 100 hours or if restricted	Carry a spare. Ethanol blends absorb moisture; replace at signs of water or debris.	Fuel Filters
Water pump impeller/kit	Every 200 hours or 2 seasons (sooner in sandy/silty water)	Replace if telltale is weak/intermittent or overheat alarm occurs.	Tohatsu Water Pump Repair Kits
Anodes (internal & trim tab)	Inspect every 50 hours; replace when 50% depleted	Internal anodes protect water passages; trim-tab anode also helps correct steering torque.	Anodes
Propeller & hardware	Check every outing; service seasonally	Remove line, inspect for dings, grease shaft, verify cotter pin shear integrity.	Propellers
Thermostat	Inspect annually; replace as needed	Sticking thermostats can cause cold running or overheat; replace if corroded.	Tohatsu Outboard Parts

Common Symptoms & Quick Checks

Symptom	Check First	Related Parts
Weak telltale or overheat alarm	Inspect intake screens, impeller condition, thermostat operation, and for debris in passages.	Water pump kit, thermostat, intake screens, internal anodes
Poor acceleration / loss of power	Check spark plug condition, fuel quality/venting, in-line filter restriction, and prop damage/pitch.	Spark plugs, fuel filter, propeller
Hard starting or rough idle	Verify choke/enrichment function, look for stale fuel or air leaks, and inspect idle mixture/idle speed.	Spark plugs, fuel filter, carburetor repair kit
Steering pulls to one side	Adjust the trim-tab anode angle to reduce steering torque; verify prop condition.	Trim-tab anode, propeller
Gearcase noise or milky gear oil	Check drain plug gaskets, seals, and shaft play; drain and inspect lubricant for metal.	Lower unit seal kit, bearings, gear lube

FAQs

Are parts interchangeable between 8HP and 9.8HP models?

Many routine-service items (plugs, filters, water pump components) are shared across MFS8 and MFS9.8 platforms. However, confirm model suffix, serial range, shaft length, and control type (tiller vs remote). Items like trim-tab anodes, internal anodes, and rigging hardware may vary by serial range or configuration.

When should I replace the impeller?

As a preventive measure, replace the impeller every 200 hours or two seasons—earlier if you operate in sandy/silty water or notice a weak/intermittent telltale or overheat alarms.

How often should I change the gear oil?

Change the lower-unit gear oil at least every 100 hours or annually. If the oil looks milky (water intrusion) or metallic, service the seals before further use.

What information do I need to confirm part compatibility?

Provide the full model code (e.g., MFS8 or MFS9.8) with suffix, serial number, shaft length (S/L), start type (manual/electric), and control type (tiller/remote). Photos of the nameplate and the existing part also help ensure a perfect match.

Ready to find parts by horsepower, year, and model? Browse the main Tohatsu collection to locate the exact components for your outboard.

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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.