Mercruiser 7.4 Liter MPI Specifications

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The MerCruiser 7.4-liter MPI (7.4L MPI), is an boat engine manufactured by Mercury Marine, a American company headquartered in Fond du Lac, Wisconsin. The 7.4L MPI is an inboard motor which, when attached to a sterndrive unit, propels the vessel through the water.

Performance Specs

The MerCruiser 7.4L MPI is a gasoline powered, fuel injected, 8-cylinder, 4-cycle marine engine. It delivers 310 horsepower (HP) to the propeller shaft at a maximum of 4,200 to 4,600 RPM at WOT (revolutions per minute at wide open throttle). It is a large engine with 454 cubic inches (7.4 liters) of displacement.

Electrical Specs

The 7.4L MPI comes standard with a 72-amp alternator that charges the 12-volt, negative ground electrical system. The recommended battery rating is a minimum of 650 CCA (cold cranking amps) with 150 Ah (amps per hour).

Other Specs

For purposes of a tune up, the correct timing setting is 8 degrees BTDC (before top dead center) at idle of 600 RPM. The firing order of the cylinders is 1-8-4-3-6-5-7-2. Oil pressure is 30-70 PSI (pounds per square inch) at 2,000 RPM and 4 PSI at idle. Normal operating temperature of the 7.4L MPI is 160 degrees Fahrenheit and is controlled by a thermostat.


About the Author

Paul McCormick began writing professionally in 2009 and is currently a freelance writer. He has two books published: "Dementia: The Journey of Caring for our Father at Home" and "Dill Pickle Love." The latter book is already being taught in seminars in Colorado. McCormick received his Bachelor of Arts from Grand Canyon College.

Photo Credits

  • Zubin Shroff/Digital Vision/Getty Images