Tohatsu MFS6CS Troubleshooting
| Engine Model: Tohatsu MFS6CS |
| Engine Type: 4-stroke 1-cylinder OHV gasoline outboard engine |
| Total Displacement: 7.5 cu.in (123 cc) |
| Rated Engine Power: 6 Hp (4.4 kW) at 6000 rpm |
| Fuel System: Carburetor |
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| Engine starts up hard or will not start |
No fuel in fuel tank - Add gasoline.
Wrong grade of gasoline - Use correct fuel grade.
Dirty fuel lines - Inspect and clean.
Defective spark plug wire connection - Check the spark plug wire connection, repair or replace.
Faulty spark plug - Install new spark plug.
Plugged fuel filter - Fuel filter needs to be replaced.
Carburetor is not working properly - Inspect and adjust.
Restricted fuel lines - Service fuel lines.
Fuel tank air vent closed or restricted - Open or service air vent.
Fuel pump defective - Replace or rebuild fuel pump.
Choke cable is damaged or not adjusted properly - Replace cable or adjust properly.
Incorrect valve clearance - Check and adjust.
Valve timing is incorrect - Adjust valve timing correctly.
| Engine starts and then stalls |
Defective spark plug - Replace spark plug.
Carburetor is faulty or clogged - Clean or change carburetor.
Faulty ignition coil - Install a new ignition coil.
Fuel tank air vent clogged or closed - Open or clean air vent.
Fuel pump malfunction - Replace or rebuild fuel pump.
Damaged choke system - Change choke system components as required.
Valve clearance is not correct - Adjust to proper valve clearance.
Incorrect valve timing - Adjust valve timing as required.
Loose or broken valve springs - New valve springs need to be installed.
Stuck valves - Valves must be cleaned.
Ignition system failure - Check ignition system and replace faulty parts.
Clogged or damaged fuel pump - Test fuel pump and replace if necessary.
Problems with carburetor adjustment - Adjust as required.
Restricted fuel lines - Clean fuel lines.
Closed or restricted fuel tank air vent - Open or service air vent.
Fuel filter is plugged - Replace fuel filter.
Gaskets are damaged - Install new gaskets.
Clogged water intake - Clean and wash as required.
Choke system malfunction - Inspect and replace choke system components.
Excessive engine load - Reduce engine load.
Too lean carburetor mixture - Adjust carburetor properly.
Ignition timing is wrong - Set the ignition timing correctly.
Damaged thermostat - Replace thermostat.
Damaged water pump - Change water pump.
Propeller pitch or diameter incorrect - Install correct propeller.
Damaged or improper size of propeller - Replace propeller.
Outboard engine is positioned too low or too high - Mount the motor as required.
Engine oil level is low - Fill the crankcase with engine oil.
Oil pump is defective - Install new oil pump.
Water intake screen is dirty - Need to clean or wash.
Incorrect valve setting - Valves needs to be adjusted properly.
| Abnormal engine knocking or noise |
Low octane gasoline - Change gasoline.
Engine overload - Reduce load.
Too low idle RPM - Adjust idle speed.
Fuel pump is faulty or clogged - Check fuel pump and change if required.
Main bearings or crankshaft are worn out - Change or repair worn components.
Damaged cylinder bore or piston rings - Change defective parts.
Incorrectly adjusted or clogged carburetor - Service or properly adjust carburetor.
Fuel pump is defective or dirty - Check fuel pump and change if required.
Ignition system is defective - Test ignition and replace failed parts.
Blown cylinder head gasket - Change cylinder head gasket.
Powerhead parts are faulty - Replace defective components.
Stuck or burned valves - Service or change valves.
Incorrect propeller selection - Install correct propeller.
Damaged or bent propeller - Replace propeller.
Incorrect outboard motor mounting height - Have motor adjusted to proper transom height.
Trim angle is incorrect - Make the correct trim angle adjustment.
| Engine using too much gasoline |
Carburetor main jet is improperly adjusted - Adjust main jet as required.
Spark plug is defective or loose - Tighten or change the spark plug.
Sleeve, piston, or rings are damaged - Replace defective parts.
Damaged or improper size of propeller - Replace propeller.
Propeller shaft damaged - Replace propeller shaft.
Weeds wraped around propeller - Clean the propeller.
Motor mounting bolt is loose - Tighten the bolt as required.
Steering pivot is loose or damaged Tighten correctly or replace.
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| Outboard Engines Technical Specifications |
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