TOHATSU MFS 3.5B - User Manual

Questions and Answers

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John FryAug 18, 2025
Why is my TOHATSU Outboard Motor engine failing to start?
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  Andrea WilliamsAug 18, 2025
  Several factors can prevent your TOHATSU Outboard Motor from starting. It could be due to: an empty fuel tank (fill it up); 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 these parts); an incorrect spark plug (install the specified one); a dirty spark plug (clean it); a weak or absent spark (check ignition components); a short circuit in the engine stop switch (inspect and repair it); incorrect ignition timing (adjust it); a missing lock plate on the stop switch (fit the lock plate); or disconnected wires or a loose ground connection (reconnect the wires or secure the ground).
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smithdestinyAug 20, 2025
Why won't my TOHATSU MFS 3.5B start?
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  Benjamin LyonsAug 20, 2025
  If your TOHATSU Outboard Motor engine won't start, several factors could be at play. First, check the fuel level and refill if it's empty. Inspect the fuel hose for any deformities or damage, replacing it if necessary. Ensure the air vent on the fuel tank is open. Clogged components like the fuel filter, fuel pump, or carburetor can also prevent starting, so clean or replace them. Verify you're using the recommended engine oil and gasoline. An excessive fuel supply or poor carburetor adjustment might also be the issue; adjust accordingly.
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Phillip MartinAug 22, 2025
What to do if my TOHATSU Outboard Motor engine starts but stops soon after?
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  Dawn WebbAug 23, 2025
  If your TOHATSU Outboard Motor starts and then stops quickly, it might be caused by a deformed or damaged fuel hose, in which case you should replace it. Another cause could be a closed air vent on the fuel tank, so open it. It may also be due to a clogged fuel filter, fuel pump, or carburetor, so clean or replace those. Using the incorrect engine oil or gasoline could also be the problem, so make sure to use the correct ones. Finally, poor carburetor adjustment can cause this issue, so adjust the carburetor.
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brett72Aug 26, 2025
Why is the engine speed abnormally high on my TOHATSU MFS 3.5B?
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  Carrie WalkerAug 26, 2025
  An abnormally high engine speed in your TOHATSU Outboard Motor could stem from a few reasons. Check for a closed air vent on the fuel tank and open it. A clogged fuel filter, fuel pump, or carburetor could be the culprit, so clean or replace them. Ensure you're using the correct engine oil and gasoline. Insufficient cooling water flow due to a clogged or defective pump can also cause this, so fix the cooling water issue. The propeller might be incorrect, so choose the correct one, or it may be damaged and bent, requiring replacement.
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Kayla IbarraAug 27, 2025
What causes abnormally low engine speed in a TOHATSU Outboard Motor?
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  Nicole MccartyAug 27, 2025
  If your TOHATSU Outboard Motor's engine speed is abnormally low, it could be due to a closed air vent on the fuel tank, so open it. Another possibility is a clogged fuel filter, fuel pump, or carburetor, so clean or replace them. An unbalanced load on the boat can also cause this issue, so balance the load.
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maria66Aug 30, 2025
What to do if my TOHATSU MFS 3.5B Outboard Motor is overheating?
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  Haley HowardAug 30, 2025
  If your TOHATSU Outboard Motor engine is overheating, it could be due to insufficient cooling water flow caused by a clogged or defective pump; inspect the cooling system for clogs or defects. Another potential cause is a faulty thermostat, which should be replaced.
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Tracy DonaldsonSep 2, 2025
How to fix poor idling on my TOHATSU Outboard Motor?
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  Heather LewisSep 2, 2025
  Poor idling in your TOHATSU Outboard Motor can be caused by several factors. Start by checking if the air vent on the fuel tank is closed and open it. A clogged fuel filter, fuel pump, or carburetor can also cause this, so clean or replace them. Make sure you're using the correct engine oil and gasoline. Insufficient cooling water flow, due to a clogged or defective pump, or a faulty thermostat can also lead to poor idling, so fix the cooling water issue or replace the thermostat.
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Meredith WintersSep 4, 2025
Why does my TOHATSU Outboard Motor have poor acceleration?
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  dennisryanSep 4, 2025
  Poor acceleration in your TOHATSU Outboard Motor can occur if you are using the incorrect engine oil or gasoline. It may also happen due to an excessive fuel supply or poor carburetor adjustment. In these cases, adjust the fuel supply and/or adjust the carburetor.
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Brandy ThompsonSep 6, 2025
How to fix a TOHATSU MFS 3.5B Outboard Motor that starts then stops?
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  Richard MartinSep 7, 2025
  If your TOHATSU Outboard Motor starts but stops soon after, the ignition timing might be incorrect; check and correct it. Also, ensure the lock plate is fitted to the stop switch. Inspect all electrical connections for disconnections or loose ground connections and secure them.
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Ronald MorganSep 9, 2025
Why is my TOHATSU MFS 3.5B Outboard Motor engine overheating?
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  lisapalmerSep 9, 2025
  If you are experiencing overheating in your TOHATSU Outboard Motor engine, it could be due to several reasons: * Insufficient cooling water flow, possibly from a clogged or defective pump. * A faulty thermostat. * Cavitation or ventilation issues. * Incorrect propeller selection, or a damaged propeller. * Improper thrust rod position. * An unbalanced load on the boat. * The transom being either too high or too low. It is recommended to consult the check list below to determine the cause and to take the proper action.