TOHATSU MFS 25B - User Manual

Questions and Answers

C
Cynthia AlexanderJul 31, 2025
Why is my TOHATSU MFS 25B Outboard Motor engine difficult to start?
- M
  Melissa BrownJul 31, 2025
  If your TOHATSU Outboard Motor engine is hard to start, several factors could be at play. Start by checking if the fuel tank is empty and fill it if necessary. Ensure the fuel system connections are correct and inspect the fuel line for any leaks that might be letting air in. A deformed or damaged fuel hose should be replaced. Make sure the air vent on the fuel tank is open. The fuel filter or fuel pump might be clogged, requiring cleaning or replacement. Verify you're using the specified engine oil and recommended gasoline. Ensure you're adequately priming the fuel system. Finally, check the water temperature or MAP sensor and their wiring for any issues.
J
John ThompsonAug 4, 2025
What to do if my TOHATSU MFS 25B engine runs erratically?
- K
  Katherine MartinAug 5, 2025
  If your TOHATSU Outboard Motor engine runs erratically, begin by checking the fuel system connections and inspecting the fuel line for air leaks. Ensure the fuel filter and pump are free from clogs, cleaning or replacing them if needed. Verify that you're using the correct gasoline. Confirm the motor is shifted into neutral. Inspect the battery and its connections for looseness or corrosion. If the ignition key switch is faulty, replace it. Finally, examine the wiring and electrical connections for any issues and repair as necessary.
J
Julie WhiteAug 9, 2025
How to improve low engine speed on my TOHATSU MFS 25B?
- A
  Aaron SmithAug 10, 2025
  If your TOHATSU Outboard Motor has low engine speed or poor boat speed, ensure you are using the correct engine oil. Check the water temperature or MAP sensor and wiring connections. Address any low compression issues and clean carbon deposits in the combustion chamber. Adjust the valve clearance if it's incorrect. Check the oil level and pump functionality, and clear any blockages from the pump for insufficient cooling water flow. Replace a faulty thermostat if necessary. Verify that the propeller is correct and not damaged. Adjust the thrust rod position if improper. Balance the load on the boat and adjust the transom height if it's too high or low.
A
Abigail SteeleAug 14, 2025
What to do if the starter motor on my TOHATSU MFS 25B Outboard Motor will not crank?
- W
  wrightkristineAug 15, 2025
  If the starter motor on your TOHATSU Outboard Motor won't crank, begin by checking the 20 Amp fuse in the starting circuit and replace it if it's blown. Inspect the engine stop switch for a short circuit and repair if necessary. Ensure all wires and ground connections are securely connected. Make sure the gear is shifted into the neutral position. If the ignition key switch is faulty, it will need to be replaced. Check all wiring and electrical connections for faults and repair them. Lastly, the starter motor or starter solenoid might have failed and require replacement.
G
georgewilliamsAug 19, 2025
How to troubleshoot an inoperative Power Trim & Tilt on a TOHATSU Outboard Motor?
- C
  Chelsea ChambersAug 19, 2025
  If the Power Trim & Tilt on your TOHATSU Outboard Motor is inoperative, the power trim & tilt switch or solenoid may be defective and need replacement. Also, check for incorrect wiring, disconnections, or poor connections, and correct them as necessary.
J
James Adams MDAug 25, 2025
Why won't the battery hold charge on my TOHATSU MFS 25B?
- B
  Brandon WhitneyAug 25, 2025
  If the battery on your TOHATSU Outboard Motor will not hold a charge, check the battery and its connections for looseness or corrosion. Also, inspect the 20 Amp fuse in the starting circuit and replace it if it's blown.

Summary

General Safety Guidelines

Emergency Stop Switch

Details the function and use of the emergency stop switch for safety.

Safe Operation of Boat

Operator responsibility for safety and knowledge of correct boat and motor operation.

Warning Label Locations and Meanings

Outboard Motor Installation

Mounting the Outboard Motor

Instructions for securely mounting the outboard motor onto the boat's transom.

Installing Remote Control Devices

Installing the Battery

Pre-Operation Preparations and Checks

Recommended Gasoline Types

Specifies approved gasoline types, octane ratings, and precautions for alcohol content.

Recommended Engine Oil

Guidelines for selecting and using appropriate engine oil for performance and longevity.

Break-In Procedure

Instructions for breaking in the new outboard motor for optimal performance.

Warning System

Explains the warning indicators, faults, and remedies for abnormal conditions.

Engine Operation Procedures

Before Starting Checks

Filling the Fuel Tank

Procedures for safely filling the fuel tank, including cap operation and venting.

Feeding the Fuel

Steps for priming the fuel system using the primer bulb.

Starting the Engine

Instructions for starting the outboard motor using various methods.

Warming up the Engine

Propeller Selection

Forward and Reverse Operation

Procedures for shifting into forward and reverse gears safely.

Stopping the Engine

Steps for safely shutting down the outboard motor.

Trim Angle Adjustment

How to adjust the trim angle for optimal boat performance and stability.

Tilt Up, Down, and Shallow Water Operation

Procedures for tilting the motor and operating in shallow water.

Motor Removal, Carrying, and Storage

Removing the Outboard Motor

Component Adjustments

Trim Tab Adjustment

Inspection and Maintenance Schedule

Daily Inspection

Routine checks to perform before and after using the outboard motor.

Replacing the Propeller

Replacing the Spark Plugs

Periodic Inspection

Replacing Engine Oil

Replacing Gear Oil

Off-Season Storage

Pre-Season Check

Motor Submerged in Water

Checking After Striking Underwater Object

Troubleshooting Common Issues

TOHATSU MFS 25B Specifications

General

Cylinders	2
Fuel System	Carburetor
Starting System	Manual
Cooling System	Water-Cooled
Gear Ratio	2.08:1
Horsepower	25 hp
Shaft Length	20 in
Fuel Type	Gasoline
Alternator Output	12V