Mercury 400R Verado Troubleshooting
| Engine Model: Mercury Verado 400R |
| Engine Type: 4-stroke 6-cylinder DOHC 24-valve supercharged gasoline outboard engine |
| Total Displacement: 158.5 cu.in (2.6 L) |
| Rated Engine Power: 400 Hp (298 kW) at 7000 rpm |
| Fuel System: Sequential multi-point electronic fuel injection (EFI) |
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| Engine will not start or hard to start |
No gasoline in tank - Fill it up.
Low-quality gasoline - Use correct gasoline grade.
There is air in the fuel system - Bleed the system.
Loose or disconnected spark plug wire - Inspect spark plug wiring connection, change or repair.
Spark plug is faulty - Change spark plug.
Fuel filter is dirty - Fuel filter needs changing.
Vapor separator needle valve is worn or defective - Install new needle valve.
Dirty fuel lines - Fuel lines need to be cleaned.
Fuel tank air vent clogged or closed - Open or clean air vent.
Fuel feed pump failure - Replace or repair fuel pump.
Not adjusted or damaged throttle cable - Change cable or adjust properly.
Excessive valve clearance - Adjust valve clearance.
Valve timing is wrong - Set the valve timing properly.
Low fuel pressure - Check system for fuel leaks or check low pressure fuel pump.
Fuel injector is faulty or clogged - Replace or clean as required.
Fuel regulator is not operating - Change fuel regulator.
ECM is faulty - Install new ECM.
| Engine stalls after starting |
Defective spark plug - Change spark plug as required.
Damaged or wear vapor separator needle valve - Change vapor separator needle valve.
Faulty ignition coil - Install a new ignition coil.
Fuel tank air vent clogged or closed - Fuel tank air vent need to be opened or cleaned.
Faulty fuel pump - Install new pump or repair it.
Choke system is damaged - Check and repair choke system.
Incorrect valve clearance - Check and adjust.
Incorrect valve timing - Set the valve timing properly.
Broken or loose valve springs - New valve springs need to be installed.
Valves are stuck - Clean the valves.
Bad compression - Check and change damaged parts.
Fuel filter is plugged - Install new filter.
Fuel injector is dirty or worn - Replace or clean as required.
Insufficient engine oil - Check oil level and add oil as required.
Oil pump failure - Oil pump need to be replaced.
Water intake is clogged - Need to clean or wash.
Defective thermostat - Thermostat need to be replaced.
Water pump malfunction - Water pump need to be replaced.
Ignition system malfunction - Check ignition and replace faulty components.
Fuel pump is defective or dirty - Clean or replace fuel pump.
Vapor separator needle valve is worn or defective - Change vapor separator needle valve.
Restricted fuel lines - Fuel lines must be clean.
Closed or clogged fuel tank air vent - Open or clean air vent.
Fuel filter is clogged - Change fuel filter.
Intake manifold is air leaking - Change intake manifold gasket.
Water intake is blocked - Need to clean or wash.
Throttle valve and throttle link are damaged or worn - Change faulty parts.
Clogged or worn fuel injector - Clean or replace if necessary.
Excessive engine load - Reduce engine load.
Fuel pump or fuel injector is clogged - Clean or replace as required.
Improper ignition timing - Adjust ignition timing as required.
Thermostat failure - Change thermostat.
Water pump is defective - Replace water pump.
Propeller pitch or diameter incorrect - Check the propeller size.
Damaged or improper size of propeller - Have propeller repaired or replaced.
Outboard engine is mounted too high or too low - Position the engine correctly.
Lack of engine oil - Add oil to the engine crankcase.
Damaged oil pump - Change oil pump.
Water intake is blocked - Clean and wash as required.
Wrong valve setting - Adjust valves correctly.
Stale or low octane fuel - Change fuel.
Engine overload - Reduce engine load.
Improperly adjusted low idle speed - Correct the settings.
Fuel pump is damaged or dirty - Test fuel pump and replace if necessary.
Worn main bearings or crankshaft - Need to install new components.
Piston rings or cylinder bore are damaged - Change defective parts.
Fuel lines clogging - Clean fuel system lines.
Damaged fuel injector - Check fuel injector and change if required.
Fuel pump is dirty or defective - Test fuel pump and replace if necessary.
Defective ignition - Test ignition and replace failed parts.
Cylinder head gasket is worn - Replace the head gasket.
Powerhead parts are faulty - Replace defective components.
Stuck or burned valves - Replace or service valves.
Improper propeller diameter or pitch - Install correct propeller.
Propeller bent or damaged - Have propeller repaired or replaced.
Incorrect outboard motor mounting height - Have motor adjusted to proper transom height.
Trim angle is incorrect - Adjust trim angle correctly.
| Engine uses too much fuel |
Fuel injector is faulty or clogged - Replace or clean as required.
Loose or faulty spark plug - Tighten or replace spark plug.
Worn rings, piston, or sleeve - Replace defective components.
ECU failure - Install new ECU.
| Motor vibrates excessively |
Damaged or improper size of propeller - Replace propeller.
Damaged propeller shaft - Replace propeller shaft.
Weeds clogs the propeller - Remove weeds from propeller.
Motor mounting bolt is loose - Tighten bolt.
Steering pivot is loose or damaged Tighten or replace.
| Starter motor is not working |
Battery capacity is low - Charge the battery.
Battery is not holding charge - Service charging system or change battery.
Battery cables are disconnected or terminals are faulty - Check battery wires and service or replace terminals.
Starter motor is faulty - Replace or repair starter.
| Trim motor runs but trim system does not move up or down |
Oil insufficient - Fill up oil.
Damaged pump assembly - Inspect pump and change as required.
Manual release valve leaking - Close the valve or change it.
Broken motor or pump driveshaft - Change worn component.
| Trim does not fully up or down |
Defective pump assembly - Replace pump.
Tilt ram piston ball is in wrong position - Service or repair.
Damaged tilt ram piston O-ring - Change O-ring.
Oil insufficient - Checking oil level and add if necessary.
Lower check valve is not properly secured in port side trim ram - Install valve correctly.
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