MerCruiser 5.7 MPI User Manual (English)

Questions and Answers:

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Calvin CampbellJul 31, 2025
Why my MerCruiser 5.7 MPI will not start?
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  Debbie StephensJul 31, 2025
  If your MerCruiser Engine won't start or is hard to start: * Check the lanyard stop switch. * Ensure you are following the correct starting procedure. * Verify there is sufficient fuel supply by filling the fuel tank or opening the valve. * Replace the fuel filter if it's clogged. * Drain and refill the fuel tank with fresh fuel if the current fuel is stale or contaminated. * Replace any kinked fuel lines or clear obstructions from the fuel line or tank vent line using compressed air. * Check the wire connections. * If these steps don't resolve the issue, it could be a faulty ignition system component or an EFI system fault, which may require professional service.
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James SmithAug 4, 2025
What to do if MerCruiser Engine runs rough?
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  Dustin BlairAug 4, 2025
  If your MerCruiser Engine runs rough, misses, or backfires, consider these potential causes and solutions: * Replace the fuel filter if it is clogged. * If the fuel is stale or contaminated, drain the tank and fill it with fresh fuel. * Replace any kinked fuel lines or clear obstructions from the fuel or fuel tank vent line using compressed air. * Clean the flame arrestor. For issues related to low idle speed, a faulty ignition system component, or an EFI System fault, consult a qualified technician.
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Jay LeeAug 8, 2025
How to improve poor performance of MerCruiser Engine?
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  Renee NelsonAug 8, 2025
  If your MerCruiser Engine is showing poor performance, here are a few things to investigate: * Inspect the throttle cable and linkages to ensure the throttle is fully opening. * Consider replacing the propeller if it's damaged or improper. * Drain excessive bilge water and identify the cause of entry. * Reduce the load or redistribute it more evenly if the boat is overloaded or improperly loaded. * Clean the flame arrestor. * Clean or repair the boat bottom if it's fouled or damaged. If the issue persists, it may be related to ignition problems, engine overheating or EFI System fault, which may require professional service.
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Timothy SimpsonAug 12, 2025
What to do if the MerCruiser 5.7 MPI Engine starter motor won't crank or cranks slowly?
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  Heather KaufmanAug 12, 2025
  If the MerCruiser Engine's starter motor won't crank the engine or cranks it slowly, here's what to check: * Ensure the battery switch is turned on. * Confirm the remote control is in the neutral position. * Inspect and reset any open circuit breakers, or replace blown fuses. * Examine all electrical connections and wires, especially battery cables; clean and tighten any loose or dirty connections. * Test the battery and charge it if necessary, replace it if it's bad. * Verify that the lanyard stop switch is not activated.
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Steven SandersAug 17, 2025
Why MerCruiser 5.7 MPI Engine does not recharge?
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  Nicole TurnerAug 17, 2025
  If your MerCruiser Engine is not recharging, consider the following: * Turn off any non-essential accessories to reduce the current draw from the battery. * Replace or adjust the alternator drive belt if it is loose or in poor condition. * Test the battery and replace it if necessary. * Check all associated electrical connections and wires, especially battery cables, for looseness or dirtiness; clean and tighten faulty connections and repair or replace any damaged wiring. * Test the alternator output; replace the alternator if necessary.
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Karen MorrisAug 21, 2025
Why is the MerCruiser 5.7 MPI Engine wheel difficult to turn?
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  Shelly MckinneyAug 21, 2025
  If the wheel of your MerCruiser is jerking or difficult to turn: * Check the power steering pump fluid level for leaks and refill the system with fluid if needed. * Replace or adjust the drive belt if it's loose or in poor condition. * Lubricate the steering components. For loose or missing steering fasteners or parts, or contaminated power steering fluid, consult a qualified technician.
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lowesaraAug 26, 2025
Why MerCruiser 5.7 MPI Engine remote control is difficult to move?
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  Kelly SmithAug 26, 2025
  If the remote control for your MerCruiser Engine is difficult to move, has excessive play, or makes excessive sounds: * Lubricate the shift and throttle linkage fasteners. * Remove any obstruction in the shift or throttle linkages. For loose or missing shift and throttle linkages, or a kinked shift or throttle cable, consult a qualified technician.

MerCruiser 5.7 MPI Specifications

General

Engine Type	V8
Fuel System	Multi-Port Fuel Injection (MPI)
Horsepower	300 HP
Ignition	Electronic
Cylinders	8
Fuel Type	Gasoline
Alternator	65 amp
Compression Ratio	9.4:1
Fuel Requirement	87 octane (minimum)
Displacement	5.7L (350 cu in)
Max RPM	5000 RPM