Tohatsu MD50B2 Troubleshooting
| Engine Model: Tohatsu MD50B2 |
| Engine Type: 2-stroke 3-cylinder gasoline outboard engine |
| Total Displacement: 42.5 cu.in (697 cc) |
| Rated Engine Power: 50 Hp (36.8 kW) at 5850 rpm |
| Fuel System: Two stroke low pressure direct injection (TLDI) |
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| Engine won't start or difficult to start |
No fuel in fuel tank - Fill fuel up.
Wrong fuel grade - Change gasoline.
Dirty fuel system - Check and clean.
Spark plug wiring connection is defective - Inspect spark plug wiring connection, change or repair.
Spark plug is faulty - Spark plug need to be replaced.
Dirty fuel filter - Fuel filter needs changing.
Clogged fuel lines - Fuel lines need to be cleaned.
Low fuel pressure - Check system for fuel leaks or check low pressure fuel pump.
Low air pressure - Check air system components.
Wiring harness connections are damaged - Inspect harness connections.
Damaged ignition system - Check ignition system components and change if necessary.
Fuel feed pump is faulty - Change fuel feed pump.
Fuel injector is dirty or worn - Clean or replace as required.
Electronic control modul is not operating - Replace ECM.
Worn or defective reed valve - Replace reed valve.
| Engine starts and immediately shuts off |
Spark plug is damaged - Change spark plug.
Defective ignition coil - Install a new ignition coil.
Pulse pump is faulty - Install new fuel pump.
Restrictions in fuel system - Clean fuel system.
Clogged fuel filter - Fuel filter needs changing.
Ignition failure - Check ignition system and replace faulty parts.
Damaged spark plug - Change spark plug as required.
Fuel pump is dirty or defective - Service or replace fuel pump.
Low air pressure - Check air system components.
Restricted fuel lines - Clean fuel lines.
Fuel filter is clogged - Replace fuel filter.
Defective direct injector - Replace as required.
Engine overload - Reduce engine load.
Bad ignition timing - Ignition timing needs to be set properly.
Defective thermostat - Install new thermostat.
Defective water pump - Install new water pump.
Incorrect propeller selection - Replace propeller.
Damaged or improper size of propeller - Replace propeller.
Outboard motor is mounted too high or too low - Mount the motor as required.
Low octane fuel - Change gasoline.
Engine overload - Load reducing required.
Incorrect low idle setting - Correct idle settings.
Fuel pump is damaged or dirty - Service or change fuel pump.
Crankshaft or main bearings wear - Need to install new components.
Piston rings or cylinder bore are worn - Replace faulty components.
Fuel pump is dirty or defective - Check fuel pump and replace if necessary.
Ignition system is defective - Inspect ignition system and change faulty parts.
Worn powerhead components - Replace defective components.
Low fuel pressure - Check low pressure fuel pump or check system for fuel leaks.
Low air pressure - Inspect air system for leaks.
Bad compression - Normalize compression.
Fuel delivery problem - Check fuel system.
Fuel regulator leaks - Leak must be repaired.
Plugged fuel filter - Fuel filter needs to be replaced.
Damaged or clogged fuel injector - Replace or clean as required.
Manifold fuel leak - Leak must be repaired.
Incorrect propeller selection - Check the propeller size.
Damaged or improper size of propeller - Have propeller repaired or replaced.
Outboard motor mounting height is set incorrectly - Adjust the engine to correct transom height.
Incorrect trim angle - Adjust trim angle.
Loose or defective spark plug - Re-tighten or change the spark plug.
Sleeve, piston, or rings are damaged - Replace defective parts.
Excessive engine load - Reduce engine load.
Fuel injectors are dirty or defective - Check fuel injectors and change if required.
| Motor vibrates excessively |
Damaged or bent propeller - Have propeller repaired or replaced.
Propeller shaft malfunction - Propeller shaft needs to be replaced.
Weeds in the propeller - Clean the propeller.
Engine mounting bolt is not tightened - Tighten the bolt as required.
Loose or faulty steering pivot - Tighten or replace.
| Starter motor is not working |
Propeller bent or damaged - Have propeller repaired or replaced.
Damaged propeller shaft - Propeller shaft needs to be replaced.
Weeds wraped around propeller - Remove and clean propeller.
Engine mounting bolt is not tightened - Tighten bolt.
| Trim motor runs but trim system does not move up or down |
Not enough oil - Need to add the oil.
Damaged pump assembly - Test pump and change if necessary.
Manual release valve leaking - Close the valve or change it.
Pump driveshaft or motor damaged - Replace worn component.
| Trim cannot be fully up or down |
Defective pump assembly - Replace pump.
Tilt ram piston ball is displaced - Service or repair.
Damaged tilt ram piston O-ring - Replace O-ring.
Not enough oil - Need to add the oil.
Lower check valve not seating in port side trim ram - Secure valve properly.
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| Outboard Engines Technical Specifications |
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