Mercury 20 Jet Troubleshooting
| Engine Model: Mercury Jet 20 Hp |
| Engine Type: 2-stroke 2-cylinder gasoline outboard engine |
| Total Displacement: 24.4 cu.in (400 cc) |
| Rated Engine Power: 20 Hp (14.9 kW) at 5500 rpm |
| Fuel System: Float type carburetor |
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| Engine doesn't start or starts hard |
Gas tank is empty - Fill it up.
Wrong fuel grade - Use correct fuel grade.
Air in fuel system - Bleed fuel system.
Disconnected or loose spark plug wire - Check spark plug wiring connection, repair or change.
Faulty spark plug - Replace spark plug.
Clogged fuel filter - Install new filter.
Carburetor not adjusted - Adjust according to instructions.
Fuel lines are dirty - Clean fuel system lines.
Closed or clogged fuel tank air vent - Fuel tank air vent need to be opened or cleaned.
Lack of fuel pump pressure - Replace or repair fuel pump.
Reed valve is faulty or worn - Install new reed valve.
| Engine starts and then shuts off |
Spark plug is damaged - Spark plug need to be replaced.
Carburetor is faulty or clogged - Carburetor needs to be replaced or cleaned.
Ignition coil is not working - Replace ignition coil as necessary.
Closed or clogged fuel tank air vent - Fuel tank air vent need to be opened or cleaned.
Fuel pump pressure is low - Install new fuel pump or rebuild it.
Ignition system failure - Inspect ignition system and change failed components.
Fuel pump is faulty or clogged - Test fuel pump and change if necessary.
Carburetor is not working properly - Inspect and adjust.
Fuel lines are clogged - Service fuel lines.
Fuel tank air vent clogged or closed - Fuel tank air vent need to be opened or cleaned.
Fuel filter is plugged - Change fuel filter.
Gaskets are worn - Install new gaskets.
Engine overload - Reduce the load.
Carburetor is running lean - Set the carburetor properly.
Ignition timing is incorrect - Adjust ignition timing as required.
Thermostat is faulty - Change thermostat as required.
Faulty water pump - Install new water pump.
Incorrect propeller selection - 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.
Low octane gasoline - Change gasoline.
Excessive engine load - Load reducing is recommended.
Improperly adjusted low idle speed - Correct idle adjustment.
Dirty or faulty fuel pump - Clean or replace fuel pump.
Main bearings or crankshaft failure - Crankshaft or bearings need to be replaced.
Damaged cylinder bore or piston rings - Change faulty parts.
Carburetor is improperly adjusted or clogged - Adjust the carburetor properly or clean it.
Clogged or damaged fuel pump - Test fuel pump and change if necessary.
Ignition system malfunction - Inspect ignition system and change failed components.
Gaskets are damaged - Replace gaskets.
Faulty powerhead components - Replace defective parts.
Propeller pitch or diameter incorrect - Check the propeller size.
Propeller bent or damaged - Replace propeller.
Incorrect outboard motor mounting height - Have motor adjusted to proper transom height.
Trim angle is incorrect - Adjust trim angle correctly.
Improper carburetor main jet adjustment - Adjust the carburetor main jet correctly.
Loose or faulty spark plug - Change or re-tighten spark plug.
Worn sleeve, piston, or rings - Replace defective components.
| Engine vibrates excessively |
Damaged or bent propeller - Have propeller repaired or replaced.
Propeller shaft malfunction - Propeller shaft needs to be replaced.
Weeds clogs the propeller - Clean the propeller.
Motor mounting bolt is loose - Tighten bolt.
Steering pivot is faulty or loose Tighten or replace.
| Starter motor is not working |
Battery capacity is low - Charge the battery.
Battery is draining quickly - Battery needs service or replacement.
Bad battery terminals or disconnected wiring - Check battery wires and service or replace terminals.
Starter motor failure - Repair or install a new starter.
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| Outboard Engines Technical Specifications |
| Small Engines Technical Specifications |
| Car Engines Technical Specifications |
| Industrial Engines Technical Specifications |
