Mercury 250 EFI Saltwater problems
| Engine Model: Mercury Saltwater 250 Hp |
| Engine Type: 2-stroke 6-cylinder gasoline outboard engine |
| Total Displacement: 185.9 cu.in (3047 cc) |
| Rated Engine Power: 250 Hp (186.5 kW) at 5800 rpm |
| Fuel System: Electronic fuel injection (EFI) |
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| Engine starts hard or doesn't start |
No gasoline in tank - Add fuel.
Low-quality gasoline - Use quality gasoline.
Air in the fuel pipes - Bleed the fuel pipes.
Damaged spark plug wiring connection - Check the spark plug wire connection, repair or replace.
Spark plug is faulty - Spark plug need to be replaced.
Fuel filter is plugged - Replace fuel filter.
Dirt in the fuel lines - Fuel lines must be clean.
Discharged or worn battery - Need to charge or replace the battery.
Wiring harness connections are damaged - Check electrical wire harness connections.
Defective ignition system - Check ignition components and replace if necessary.
Pulse fuel pump is defective - Change pulse fuel pump.
Defective electric fuel pump - Replace electric fuel pump.
ECM is faulty - Replace ECM.
| Engine starts but immediately stops |
Spark plug is faulty - Install new spark plug.
Defective ignition coil - Ignition coil must be replaced.
Pulse fuel pump is defective - Change pulse fuel pump as required.
Fuel system is dirty - Clean fuel system.
Plugged final fuel filter - Replace or clean final filter.
Electric fuel pump is defective - Electric fuel pump need to be replaced.
Ignition system is defective - Test ignition and replace failed parts.
Clogged or defective fuel pump - Clean or replace fuel pump.
Fuel lines clogging - Service fuel lines.
Fuel filter is plugged - Replace fuel filter.
Engine is running overloaded - Reduce load.
Ignition timing is improper - Ignition timing needs to be adjusted correctly.
Faulty thermostat - Thermostat need to be replaced.
Water pump is defective - Install new water pump.
| Abnormal engine knocking or noise |
Stale or low octane fuel - Use proper gasoline.
Engine is under excessive load - Reduce engine load.
Incorrectly adjusted low idle speed - Adjust idling as required.
Dirty or faulty fuel pump - Clean or replace fuel pump.
Crankshaft or main bearings are worn out - Worn parts replacement required.
Damaged cylinder bore or piston rings - Replace defective components.
Dirty or faulty fuel pump - Clean or install new fuel pump.
Defective ignition - Test ignition and replace failed parts.
Faulty powerhead parts - Defective parts need to be replaced.
Failed switch box, stator, or coil - Change damaged parts.
Compression is insufficient - Correct.
Fuel delivery problem - Check and repair.
Manifold is leaking - Repair leaks.
Vapor separator is flooded - Check and correct malfunction.
| Excessive fuel consumption |
Defective or loose spark plug - Re-tighten or change the spark plug.
Worn piston, rings, or sleeve - Replace faulty components as required.
Engine overloaded - Load reducing is recommended.
Fuel injectors are clogged or faulty - Clean or replace fuel injectors.
| Motor vibrates excessively |
Propeller bent or damaged - Replace propeller.
Propeller shaft malfunction - Propeller shaft needs to be replaced.
Weeds in the propeller - Remove and clean propeller.
Engine mounting bolt is not tightened - Tighten bolt.
Damaged or loose steering pivot - Tighten correctly or replace.
Damaged or improper size of propeller - Replace propeller.
Propeller shaft damaged - Have propeller shaft replaced.
Weeds clogs the propeller - Remove weeds from propeller.
Engine mounting bolt is not tightened - Tighten the bolt as required.
| Trim motor runs but system does not move |
Oil level is insufficient - Check oil level and add oil as required.
Pump assembly faulty - Test pump and replace 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 |
Pump assembly is faulty - Change pump.
Tilt ram piston ball is in wrong position - Service or repair.
Worn tilt ram piston O-ring - Change O-ring.
Oil level low - Fill up oil.
Lower check valve not seating in port side trim ram - Install valve correctly.
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