MPI = Multiport Fuel Injection, The most efficient type of fuel injection. All cars have this system now. An MPFI unit incorporates a fuel injector at each cylinder directly above the intake valve. The intake manifold is then a regulator of air allowed into the engine with the fuel control facilitated by the ECM.

EFI= Electronically Fuel Injected, instead of a carbureted fuel delivery system this system electronically activates fuel injectors from the engines computer to spray the correct amount of fuel into the combustion chamber. MAG= Short for Magnum. Typically a higher output motor than the rest.

HORIZON= This is Mercruisers closed cooling (fresh water cooled) model. A saltwater version of various Mercruiser packages.

HO= High Output.

MERC SEACORE= The corrosion-resistant strength of the SeaCore System is the hard coat anodizing of the drive alloy. This process actually changes the molecular structure of the XK-360 aluminum alloy, creating a shield against the ravages of galvanic corrosion. Hard coat anodizing is also more abrasion resistant than case-hardened steel, but if the drive is scratched, the anodizing slows the destructive growth of corrosion through the drive surface.

ECT= Emissions Control Technology, provides cleaner exhaust without limiting performance.

VOLVO PENTA GASOLINE ENGINE SUFFIXES for models after year 2000, this gets tricky.

• The two numbers are the displacement.
• Next is the letter that indicates who made the base engine. ( G=GM, F=Ford) (OS=Ocean Series)
• After that, one or two letters that note the fuel system and/or output. L=Limited, —-S=Superior, X=Exceptional, i or I=Fuel injected (no I means carbureted).
• Then one letter for the steering system. P=Power steering, M=Manual steering, X=Exact steering, I=Inboard.
• Then a dash (-) followed by a one or two letter suffix. This is the major change from the charcoal engines before 2000.
• The first letter is the version control, this is present on all current engines. (A) is the first version, (B) is the second version, etc. There is no link between the suffix and production years. All engines with (A) were not built the same year. A 5.7GXi-B and a 5.0GXi-B are not similar. A 4.3GL-D is newer than and different from a 4.3GL-C.
• The second letter, if present is always an (F), it notes that the engine is freshwater cooled.
  Examples: 3.0GLM-C, 4.3GXi-DF, 5.0OSi-E, 8.1GXiI-B

Common Examples:

Volvo Penta Engine 5.7GXi = All pistons displace 5.7 liters in the combustion chamber. Block made by (G)GM. Exceptional fuel delivery (X). Fuel injected (i)
Volvo Penta 5.7Gi-B= Displaces 5.7L. Block made by GM(G). Fuel Injected (i). Second version of the engine (B)
Volvo Penta 8.1OSi= Displaces 8.1L. Ocean Series (OS). Fuel injected (i)
Volvo Penta 5.0GL=Displaces 5.0L. Block made by GM(G). Fuel system limited (L)
There are many other suffixes associated with this brand but these are among the most common applications for inboard cruising recreational vessels.