________________________________________________________________________________________
| Home / Outboard Engines / Mercury Engines / Mercury 15 EFI |
Mercury 15 EFI Troubleshooting
| Engine difficult to start or won't start |
Empty fuel tank - Fill fuel up.
Wrong fuel grade - Use correct gasoline grade.
Air or water in fuel system - Remove water or air from fuel system.
Defective spark plug wire connection - Inspect the spark plug wire connection, replace or repair.
Spark plug is damaged - Change spark plug.
Plugged fuel filter - Replace or clean fuel filter.
Dirty fuel lines - Clean fuel system lines.
Drained or faulty battery - Replace or charge as required.
Damaged electrical wire harness - Check wiring harness connections.
Damaged ignition system - Replace defective components.
Damaged pulse fuel pump - Install new pulse fuel pump.
Faulty electric fuel pump - Change electric fuel pump as required.
ECM is faulty - Change electronic control modul.
| Engine starts and immediately shuts off |
Spark plug is damaged - Spark plug need to be replaced.
Defective ignition coil - Install a new ignition coil.
Pulse fuel pump failure - Install new pulse fuel pump.
Fuel system is dirty - Clean fuel system.
Final fuel filter is plugged - Final filter needs to be replaced.
Defective electric fuel pump - Change electric fuel pump as required.
| Unstable engine running |
Ignition system malfunction - Test ignition and replace failed parts.
Clogged or defective fuel pump - Check fuel pump and replace if necessary.
Clogged fuel lines - Clean fuel lines.
Dirty fuel filter - Replace or clean fuel filter.
| Engine overheating |
Engine overload - Load reducing is recommended.
Bad ignition timing - Set the ignition timing properly.
Faulty thermostat - Change thermostat.
Faulty water pump - Replace water pump.
| Engine noises or knocks |
Stale fuel - Use proper gasoline.
Engine is overloaded - Load reducing required.
Improperly adjusted low idle speed - Adjustment required.
Dirty or faulty fuel pump - Test fuel pump and replace if necessary.
Main bearings or crankshaft failure - Worn parts replacement required.
Damaged cylinder bore or piston rings - Change defective parts.
| Engine power loss |
Dirty or faulty fuel pump - Service or change fuel pump.
Defective ignition - Inspect ignition system and change failed components.
Faulty powerhead parts - Replace defective components as required.
Failed switch box, stator, or coil - Replace damaged components.
Bad compression - Correct.
Fuel supply problem - Check and repair.
Manifold is leaking - Repair leaks.
Vapor separator is flooded - Normalize vapor separator functions.
| High fuel consumption |
Spark plug is loose or faulty - Replace or tighten spark plug.
Worn sleeve, rings, or piston - Replace defective components as required.
Engine is running overloaded - Load reducing required.
Clogged or damaged fuel injectors - Inspect fuel injectors and change as required.
| Trim motor runs but system does not move |
Oil insufficient - Fill up oil.
Damaged pump assembly - Check pump and replace if necessary.
Manual shut-off valve leaks - Valve need to be closed or changed.
Broken motor or pump driveshaft - Replace defective component.
| Trim does not fully up or down |
Pump assembly faulty - Change pump as required.
Tilt ram piston ball is not positioned correctly - Clean or repair.
Tilt ram piston O-ring is worn - Replace O-ring.
Not enough oil - Check and refill oil.
Lower check valve is not properly secured in port side trim ram - Install valve correctly.
________________________________________________________________________________________
________________________________________________________________________________________
| Engines Technical Specifications |