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| Home / Outboard Engines / Mercury Engines / Mercury 50 EFI |
Mercury 50 EFI Troubleshooting
| Engine will not start or difficult to start |
Empty gas tank - Fill fuel up.
Improper fuel grade - Change fuel.
Air in the fuel lines - Bleed the fuel lines.
Damaged spark plug wiring connection - Inspect the spark plug wire connection, replace or repair.
Damaged spark plug - Install new spark plug.
Clogged fuel filter - Change fuel filter.
Dirty fuel lines - Clean fuel lines.
Drained or faulty battery - Replace or charge as required.
Bad harness connections - Inspect harness connections.
Ignition system is damaged - Change defective parts.
Pulse fuel pump failure - Install new pulse fuel pump.
Defective electric fuel pump - Change electric fuel pump as required.
ECM is faulty - Replace ECM.
| Engine starts and stops |
Damaged spark plug - Spark plug need to be replaced.
Ignition coil is not working - Ignition coil must be replaced.
Pulse fuel pump failure - Pulse fuel pump need to be replaced.
Fuel system is clogged - Clean fuel system.
Plugged final fuel filter - Replace or clean final filter.
Damaged electric fuel pump - Install new electric fuel pump.
| Engine runs roughly |
Ignition system is defective - Check ignition and replace faulty components.
Fuel pump is damaged or dirty - Service or change fuel pump.
Dirty fuel lines - Service fuel lines.
Clogged fuel filter - Fuel filter needs to be replaced.
| Engine keeps overheating |
Engine is under excessive load - Reduce load.
Improper ignition timing - Adjust ignition timing correctly.
Faulty thermostat - Replace thermostat.
Defective water pump - Replace water pump.
| Engine knocking or noise |
Low octane fuel - Change gasoline.
Engine is under excessive load - Load reducing is recommended.
Low idle speed set incorrectly - Adjustment required.
Fuel pump is defective or dirty - Test fuel pump and replace if necessary.
Main bearings or crankshaft failure - Worn parts replacement required.
Cylinder bore or piston rings are damaged - Change faulty components.
| Engine power is too low |
Clogged or damaged fuel pump - Test fuel pump and replace if necessary.
Ignition system failure - Inspect ignition system and change faulty parts.
Faulty powerhead components - Defective components need to be replaced.
Failed switch box, stator, or coil - Replace faulty parts.
Compression is insufficient - Normalize compression.
Fuel supply problem - Check and repair.
Manifold is leaking - Leak must be repaired.
Vapor separator is flooded - Check and correct malfunction.
| High fuel consumption |
Loose or defective spark plug - Tighten or replace spark plug.
Rings, sleeve, or piston are damaged - Change faulty components.
Engine is running overloaded - Reduce load.
Dirty or damaged fuel injectors - Service or change fuel injectors.
| Trim motor is running but system can't move |
Insufficient oil - Checking oil level and add if necessary.
Pump assembly faulty - Test pump and replace if necessary.
Leakage of manual drain valve - Close the valve fully or replace it.
Pump driveshaft or motor damaged - Replace worn component.
| Trim cannot be fully up or down |
Damaged pump assembly - Change pump as required.
Tilt ram piston ball is displaced - Clean or repair.
Damaged tilt ram piston O-ring - Replace O-ring.
Oil level is low - Check oil level and add oil as required.
Lower check valve not seating in port side trim ram - Install valve correctly.
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| Engines Technical Specifications |