Tohatsu M9.8B Troubleshooting
| Engine Model: Tohatsu M9.8B |
| Engine Type: 2-stroke 2-cylinder gasoline outboard engine |
| Total Displacement: 10.3 cu.in (169 cc) |
| Rated Engine Power: 9.8 Hp (7.2 kW) at 6000 rpm |
| Fuel System: Carburetor |
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| Engine hard to start or will not start |
No gasoline in tank - Fill gasoline up.
Incorrect fuel grade - Use quality fuel.
Air in the fuel pipes - Bleed the fuel pipes.
Loose or disconnected spark plug wire - Check the spark plug wire connection, repair or replace.
Damaged spark plug - Change spark plug.
Fuel filter is plugged - Change fuel filter.
Carburetor not adjusted - Adjust according to instructions.
Dirt in the fuel lines - Clean fuel lines.
Closed or restricted fuel tank air vent - Fuel tank air vent need to be opened or cleaned.
Fuel pump pressure is low - Replace or rebuild fuel pump.
Reed valve is worn or damaged - Replace reed valve.
| Engine starts but immediately shuts off |
Faulty spark plug - Change spark plug.
Carburetor is clogged or faulty - Replace or service carburetor.
Ignition coil is not working - Install a new ignition coil.
Closed or restricted fuel tank air vent - Fuel tank air vent need to be opened or cleaned.
Fuel pump pressure is low - Replace or rebuild fuel pump.
Ignition system failure - Test ignition and replace failed parts.
Fuel pump is dirty or defective - Test fuel pump and replace if necessary.
Incorrect carburetor adjustment - Adjust carburetor idle mixture screw.
Restricted fuel lines - Clean fuel system lines.
Closed or clogged fuel tank air vent - Open or service air vent.
Fuel filter is dirty - Fuel filter needs changing.
Gaskets are worn - Change gaskets.
Excessive engine load - Reduce engine load.
Carburetor mixture is too lean - Set the carburetor correctly.
Ignition timing is improper - Set the ignition timing correctly.
Defective thermostat - Install new thermostat.
Water pump failure - Water pump need to be replaced.
Improper propeller diameter or pitch - Replace propeller.
Propeller bent or damaged - Replace propeller.
Outboard engine is mounted too high or too low - Mount the motor as required.
Low octane fuel - Use correct fuel.
Engine overloaded - Reduce the load.
Too low idle RPM - Adjust idle speed.
Clogged or damaged fuel pump - Service or replace fuel pump.
Main bearings or crankshaft are worn out - Replace crankshaft or bearings.
Cylinder bore or piston rings are worn - Change defective parts.
| Engine power is insufficient |
Improperly or clogged carburetor - Adjust the carburetor correctly or clean it.
Dirty or damaged fuel pump - Service or change fuel pump.
Ignition failure - Check ignition and replace faulty components.
Gaskets are worn - Install new gaskets.
Powerhead components are faulty - Replace defective components.
Improper propeller diameter or pitch - Check the propeller size.
Damaged or bent propeller - Have propeller repaired or replaced.
Motor mounted at incorrect height on transom - Adjust the engine to correct transom height.
Improper trim angle - Adjust trim angle correctly.
| Engine using too much gasoline |
Carburetor main jet is improperly adjusted - Adjust it correctly.
Spark plug is loose or defective - Tighten or replace spark plug.
Sleeve, piston, or rings are damaged - Change faulty parts.
| Engine vibrates excessively |
Damaged or bent propeller - Replace propeller.
Propeller shaft damaged - Propeller shaft needs to be replaced.
Weeds clogs the propeller - Remove weeds from propeller.
Motor mounting bolt is loose - Tighten bolt.
Steering pivot is faulty or loose Tighten or replace.
Low battery output voltage - Battery is drained, recharge it.
Battery does not hold charge - Service or replace the battery.
Disconnected wires or corroded battery terminals - Connect cables correctly or replace terminals.
Starter motor failing - Repair or replace starter.
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| Outboard Engines Technical Specifications |
| Small Engines Technical Specifications |
| Car Engines Technical Specifications |
| Industrial Engines Technical Specifications |
