TOHATSU MFS 20C - User Manual

Other manuals for TOHATSU MFS 20C

Service Manual29 pages

Questions and Answers

G
Gregory KellyAug 17, 2025
Why is my TOHATSU MFS 20C Outboard Motor engine falling to start?
- C
  castillomichelleAug 17, 2025
  If your TOHATSU Outboard Motor engine won't start, several factors could be at play. First, make sure the fuel tank isn't empty and refill it if necessary. Then, verify the fuel system connections are correctly set up. Inspect the fuel line for any potential leaks that might be letting air in. A deformed or damaged fuel hose should be replaced. Ensure the air vent on the fuel tank is open, and check for any clogs in the fuel filter, fuel pump, or carburetor, cleaning or replacing them as needed.
J
jennifermorrisAug 20, 2025
How to troubleshoot a TOHATSU MFS 20C that won't start?
- R
  richard08Aug 20, 2025
  If your TOHATSU Outboard Motor engine is failing to start, it could be due to several reasons. These include an empty fuel tank (fill it), incorrect fuel system connections (check them), air in the fuel line (inspect and seal leaks), a deformed or damaged fuel hose (replace it), a closed air vent on the fuel tank (open it), a clogged fuel filter, fuel pump, or carburetor (clean or replace), using the wrong engine oil (use the correct grade), using improper gasoline (use the recommended type), excessive fuel supply (adjust it), or poor carburetor adjustment (adjust the carburetor).
L
Lisa MarksAug 22, 2025
What to do if my TOHATSU MFS 20C Outboard Motor engine starting but stopping soon?
- H
  Howard PerezAug 22, 2025
  If your TOHATSU Outboard Motor engine starts but stops soon after, it may be due to using the wrong type of gasoline, so ensure you are using the correct one. It could also be caused by an excessive fuel supply, in which case you should adjust the fuel supply. A poor carburetor adjustment can also cause this issue, so make sure to adjust the carburetor accordingly.
G
Gabriel JacksonAug 26, 2025
What to do if the power tilt is inoperative on my TOHATSU Outboard Motor?
- T
  Theresa KimAug 26, 2025
  If the power tilt on your TOHATSU Outboard Motor is inoperative, the power trim & tilt switch may be defective, requiring replacement. Alternatively, there might be a starter motor or starter solenoid failure, which would necessitate checking and replacing the affected component.
J
jlopezAug 28, 2025
What to do if my TOHATSU Outboard Motor engine starts but stops soon?
- C
  Cody TaylorAug 28, 2025
  If your TOHATSU Outboard Motor engine starts but stops soon after, the possible causes include an empty fuel tank (fill it up), incorrect fuel system connections (check them), air entering the fuel line (inspect and seal leaks), a deformed or damaged fuel hose (replace it), a closed air vent on the fuel tank (open it), or a clogged fuel filter, fuel pump, or carburetor (clean or replace the clogged components).
W
wwarnerAug 30, 2025
What to do if the power tilt on my TOHATSU MFS 20C Outboard Motor isn't working?
- B
  Brett MurphyAug 30, 2025
  If the power tilt on your TOHATSU Outboard Motor is inoperative, it could be caused by a defective power trim & tilt switch or a defective solenoid. Inspect and replace the faulty component.
L
Louis SmithSep 2, 2025
Why is my TOHATSU Outboard Motor overheating?
- C
  Christopher SimpsonSep 2, 2025
  If your TOHATSU Outboard Motor engine is overheating, it could be due to a few reasons. Start by checking the water pump for clogs or defects that might be causing insufficient cooling water flow; clean or replace it as necessary. Another potential cause is a faulty thermostat, which should be replaced. Lastly, carbon deposits in the combustion chamber can lead to overheating, so clean the combustion chamber.
S
Savannah HowellSep 5, 2025
How to fix poor idling on my TOHATSU MFS 20C?
- A
  Amber JacksonSep 5, 2025
  Poor idling in your TOHATSU Outboard Motor can stem from several issues. Ensure you're using the specified spark plug; if not, replace it. Check the spark plug for dirt or soot and clean it. Also, check for a spark or weak spark and replace parts if needed. Incorrect ignition timing can also cause poor idling, so adjust the ignition timing. Finally, check the battery connections and charge or replace the battery if it's weak or the connections are loose or corroded.
M
Michael PearsonSep 7, 2025
Why is the engine speed abnormally low on my TOHATSU MFS 20C Outboard Motor?
- C
  Carly RobinsonSep 8, 2025
  If your TOHATSU Outboard Motor engine speed is abnormally low, it could be due to low compression, so inspect and restore compression. Another possible cause is incorrect valve clearance, which needs adjustment.
T
Tonya WarnerSep 12, 2025
Why is the engine speed abnormally high on my TOHATSU MFS 20C?
- J
  John MossSep 12, 2025
  If your TOHATSU Outboard Motor engine speed is abnormally high, it might be due to an incorrect adjustment of the throttle link, which needs to be adjusted.

Summary

Introduction

Before Reading This Manual

Provides information for inspection, service, and repair of outboard motors.

Safety Information

Explains safety statements like DANGER, WARNING, CAUTION.

About This Manual

1. Special Tools

Lists special tools required for lower unit maintenance.

2. Parts Layout

Shows parts layout for the lower unit.

Description of Pictograph

Symbols for Chapters

Symbols representing the contents of individual chapters.

Symbols for Service Items

Symbols indicating items required for service.

Symbols for Lubrication;Sealant

Symbols indicating where lubrication or sealant is applied.

Service Information

1. Identification (Engine Serial Number)

Explains where the engine serial number is stamped.

2. Work Safety

Covers fire prevention, ventilation, and personal protection.

3. Tools and Instruments

Lists test propellers and measuring instruments.

4. Pre-delivery Inspection

Details pre-delivery checks like steering handle and gear shift.

5. Break-in Operation

Explains the procedure for engine break-in.

6. Test Run

Outlines the procedure for testing the engine after installation.

7. Check After Test Run

Details checks to perform after the test run.

Service Data

1. Outline Dimensions

Table detailing various dimensions of the engine.

2. Fuel Feed System

Diagram showing the fuel flow path from the fuel tank to the carburetor.

3. Engine Lubrication System Diagram

Diagram illustrating the engine oil circulation path.

4. Cooling Water System Diagram

Diagram showing the flow of cooling water through the engine.

5. Specifications

Key performance and physical data for different models.

6. Maintenance Data

Data for inspecting engine parts like pistons, rings, and crankshaft.

7. Tightening Torque Specifications

Critical torques for various engine and lower unit bolts.

8. Sealant and Lubricant

Applications of sealants and lubricants for assembly.

Maintenance

1. Special Tools

Lists special tools needed for maintenance procedures.

2. Inspection Schedule

Schedule for inspecting various parts based on operating hours or time.

3. Inspection Items

Lists specific inspection items for the engine and systems.

Fuel System

1. Special Tools

Lists special tools for fuel system inspection.

2. Parts Layout

Parts layout for the carburetor and intake manifold/fuel pump.

3. Carburetor Inner Passages

Details of idling, off-idle, high speed, acceleration, and choking passages.

4. Inspection Items

Covers removing, disassembling, and inspecting the carburetor and fuel pump.

Power Unit

1. Special tools

Lists special tools for power unit maintenance.

2. Parts Layout

Parts layout for engine, magneto, electrical parts, etc.

3. Inspection Items

Comprehensive list of inspection items for the power unit.

Lower Unit

1. Special Tools

Lists special tools for lower unit maintenance.

2. Parts Layout

Parts layout for gear case, drive shaft housing, and drive system/water pump.

3. Inspection Items

Lists various inspection and maintenance tasks for the lower unit.

Bracket

1. Parts Layout

Parts layout for drive shaft housing, swivel bracket, clamp bracket, and tiller handle.

2. Inspection Items

Lists inspection items for throttle cable, tiller handle, and bracket components.

Electrical System

1. Special Tools

Lists tools for electrical system inspection.

2. Electrical Component Layout

Shows component layout from different views.

3. Parts Layout

Parts layout for magneto, electric parts, starter motor, and switches.

4. Ignition System and Ignition Control System

Inspection procedures for ignition sparks, plug cap, coils, and switches.

5. Starting System

Inspection procedures for fuse, starter solenoid, and starter motor.

6. Battery Charging System

Inspection procedures for charge coil and rectifier.

7. CD Unit Coupler

Checks wire harness and terminals for the CD unit.

Troubleshooting

1. Troubleshooting Chart

A chart listing symptoms, estimated causes, and reference pages.

2. Power Unit

Covers engine starting problems and stalling issues.

3. Warning Indication... Display for Abnormalities During Operation

Explains warning indications for buzzer, cowl lamp, and tachometer lamp.

Wiring Diagram

MF Model

Wiring diagram for the MF model.

EF Model

Wiring diagram for the EF model.

EP Model

Wiring diagram for the EP model.

TOHATSU MFS 20C Specifications

General

Horsepower	20 HP
Output	14.7kW
Gear Ratio	2.15:1
Exhaust	Through Prop
Cylinders	2
WOT Range	5000-6000 rpm
Engine Type	4-Stroke
Fuel System	EFI (Electronic Fuel Injection)
Starting System	Electric
Weight	58 kg
Shaft Length	20 inch
Fuel Type	Unleaded Gasoline (87 Octane)
Fuel Tank Capacity	12 L
Oil Capacity	1.1 L
Alternator Output	12V
Trim Method	Manual