Tohatsu MFS6BS Troubleshooting
| Engine Model: Tohatsu MFS6BS |
| 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 difficult to start or doesn't start |
Fuel tank is empty - Add gasoline.
Wrong fuel grade - Use correct fuel grade.
Dirty fuel lines - Inspect and clean.
Damaged spark plug wiring connection - Inspect spark plug wiring connection, change or repair.
Spark plug is damaged - Change spark plug.
Fuel filter is plugged - Install new filter.
Carburetor settings incorrect - Adjusting as required.
Fuel lines clogging - Service fuel lines.
Fuel tank air vent clogged or closed - Open or service air vent.
Fuel pump defective - Replace or repair fuel pump.
Choke cable is not adjusted properly or worn - Adjust correctly or change the cable.
Valve clearance is incorrect - Adjustment procedure required.
Valve timing is wrong - Set the valve timing correctly.
| Engine starts and stalls suddenly |
Spark plug is damaged - Change spark plug as required.
Carburetor is defective or dirty - Clean or replace carburetor.
Damaged ignition coil - Replace ignition coil as necessary.
Closed or clogged fuel tank air vent - Open or service air vent.
Fuel pump defective - Replace or repair fuel pump.
Choke system malfunction - Change choke system components as required.
Valve clearance is improper - Adjust valve clearance.
Valve timing is improper - Set the valve timing properly.
Valve springs are weak or broken - Change valve springs.
Valves are stuck - Valves must be cleaned.
Ignition failure - Check ignition system and replace faulty parts.
Dirty or defective fuel pump - Service or replace fuel pump.
Carburetor is not working properly - Inspect and adjust.
Restricted fuel lines - Clean fuel system lines.
Fuel tank air vent clogged or closed - Open or service air vent.
Fuel filter is plugged - Replace or clean fuel filter.
Worn gaskets - Replace gaskets.
Water intake is blocked - Clean and wash as required.
Choke system is damaged - Change choke system components as required.
Engine is overloaded - Reduce engine load.
Too lean fuel mixture in carburetor - Set the carburetor correctly.
Wrong ignition timing - Ignition timing needs to be adjusted correctly.
Damaged thermostat - Install new thermostat.
Damaged water pump - Install new water pump.
Propeller selection improperly - Check the propeller size.
Damaged or bent propeller - Replace propeller.
Outboard engine is positioned too low or too high - Mount the motor as required.
Not enough engine oil - Need to add engine oil.
Damaged oil pump - Change oil pump.
Dirty water intake screen - Need to wash or clean.
Incorrect valve setting - Valves needs to be set correctly.
| Abnormal engine noise or knocking |
Stale fuel - Change gasoline.
Engine is running overloaded - Reduce load.
Incorrectly adjusted low idle speed - Adjust as required.
Fuel pump is dirty or defective - Check fuel pump and replace if necessary.
Main bearings or crankshaft are worn out - Change defective components as required.
Worn cylinder bore or piston rings - Replace defective components.
Clogged or improperly adjusted carburetor - Clean or correctly adjust carburetor.
Fuel pump is dirty or defective - Check fuel pump and replace if necessary.
Ignition system failure - Check ignition and replace faulty components.
Damaged cylinder head gasket - Replace cylinder head gasket.
Powerhead parts are damaged - Change defective parts.
Stuck or burned valves - Service or change valves.
Propeller pitch or diameter incorrect - Replace propeller.
Damaged or bent propeller - Replace propeller.
Engine mounted at wrong transom height - Adjust the outboard motor height correctly.
Trim angle is incorrect - Adjust trim angle correctly.
| Engine using too much gasoline |
Carburetor main jet is incorrectly adjusted - Adjust the carburetor main jet properly.
Spark plug is loose or defective - Tighten or replace spark plug.
Sleeve, piston, or rings are damaged - Change faulty components.
| Excessive engine vibration |
Damaged or bent propeller - Replace propeller.
Propeller shaft malfunction - Propeller shaft needs to be replaced.
Weeds wraped around propeller - Remove weeds from propeller.
Engine mounting bolt is not tightened - Tighten bolt.
Damaged or loose steering pivot Tighten or replace.
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| Outboard Engines Technical Specifications |
| Small Engines Technical Specifications |
| Car Engines Technical Specifications |
| Industrial Engines Technical Specifications |
