Decoding The Volvo Penta Model Numbering System
By Mike Halligan, Sales Representative
All Volvo engines come from the factory with a metal tag riveted on the engine or outdrive which has the serial number and the engine identification.
From the late eighties and up, the serial number should be ten digits in length. If you can provide us with this number, most of the time we can tell you exactly what the engine or outdrive is along with the year of production.
Routine engine maintenance, including the timely replacement of gas and oil filters on your boat is the key to a long marine engine service life. One challenge that people often face is how to correctly identify what they have for an engine.
Volvo Penta has over the years had several different methods of identification. Engines built before 1993 are painted red in color. Until the late eighties, the engines had a prefix which told you what type of application it was: inboard (MB or BB) or inboard out board (AQ), followed by a displacement or horsepower rating number, depending on the year. A letter on the end indicated the production version. So if you have an engine that says AQ131B on it, we know:
- it is an inboard/out board (AQ131B)
- it has approximately 131 shaft hp (aq131B)
- it was produced in 1986 or 87 (aq131B)
The later models in this series (early nineties) changed to a system based on displacement. Engine models had a three-digit number followed by a letter. For example, the 43 in 430 signifies that the displacement is 4.3 liters and the third digit is for model control. A 434 and a 432 are both 4.3 litter engines but the different third digits indicates a difference between the two engines. Volvo manufactured this family of engines until 1993.
Incidentally, from 1993 to 1998 or so Volvo supplied both engines and sterndrives to OMC. The drives were branded OMC Cobras but were really manufactured by Volvo. These engine models had a two-digit number and followed by a string of letters to identify the year and model. For example a4.3GLPNCA is 4.3 litters, and the:
G identifies that it is a General Motors block,
L tells you that it is limited output. L= limited, S= Superior, X= exceptional i = stands for fuel injection (the lack of and “i” means that it is carbureted)
P tells you that it has power steering,
NC identifies that it is a 1996 model year and
A is the service code for version control.
The fourth and fifth (or fifth and sixth) letters always identify the year of the particular engine in question. The year codes for different years is as follows:
MD = 1993-1994
HU = 1994-1995
NC = 1996-1997
BY = 1997-1998
WT = 1998-1999
EF = 1999-2000
From model year 2000 and up, engines were again painted red in color, and the identification methods changed. The first two numbers is now the displacement followed by a letter, which indicates the supplier of the engine block. For Ocean Series, this letter is replaced with OS and indicates it can be used with Ocean Series outdrives. One or two letters identifying the fuel system and the output (lower case i stands for fuel injection) follow the supplier ID. It should also be noted that the 3.0 will also have a letter that identifies the steering method M for manual and P for power. For example, we have a 5.7GXi-A. We know that this engine has a 5.7 liter displacement, that GM supplies it, and that is has an exceptional out put with fuel injection (Xi). We also know that this is the A version which is the first version for this engine which would come before the gxi-b or –c, but is not indicative of a specific year of production.
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Marine Parts Express is a division of Water Resources, Inc., a privately held Maine Corporation.
For all your marine engine parts needs, call us toll free at 877.621.2628, or outside the U.S. at 207.882.6165.
May 23, 2011 / mpartsexpress / 0
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