MerCruiser part numbers can be difficult to find, even on the internet. If you need a MerCruiser part and are not sure as to the correct part number for your engine, simply contact us with your engine serial number and we will use our expertise to locate the correct MerCruiser part for your application. Re: Mercury serial number to year chart It is a Mercury. 9.8 as far as i was told when i bought it. Which puts it in the 1980's. Serial number is from block, the identification plate is missing. The Bravo Two outdrive, while physically similar, is not found on engines of greater than 450 horsepower or boats that operate at speeds of greater than 55 mph. For lower-speed or lower-horsepower applications, a Mercury dealer can identify the drive by its serial number.
Mercruiser Sterndrive Gear Ratio Chart
Use this chart to determine your gear ratio before ordering a Mercruiser R-Style, Alpha 1 or Alpha 1 Gen 2 sterndrive.
Mercruiser R-Style Sterndrives (1969 - 1983)
| Engine | HP | Liters/CID | Cylinders | Gear Ratio | Tooth Count | Year |
|---|
| 2.5 Liter | 120 | 2.5/153 | 4 | 1.98 | 20-24 | 1969-1983 |
| 2.5 Liter | 130 | 2.5/153 | 4 | 1.98 | 20-24 | 1969-1983 |
| 165 | 165 | 3.7/224 | 6 | 1.65 | 24-24 | 1969-1983 |
| 470 | 170 - 190 | 4.3/262 | 4 | 1.84 | 17-19 | 1969-1983 |
| 215 - 233 | 205 - 230 | 351 | 8 | 1.5 | 20-22 | 1969-1983 |
| 260 | 260 | 5.7/350 | 8 | 1.5 | 20-22 | 1969-1983 |
Mercruiser Alpha 1 (1984 - 1990 Models)
| Engine | HP | Liters/CID | Cylinders | Gear Ratio | Tooth Count | Year |
|---|
| 2.5 Liter | 120 | 2.5/153 | 4 | 1.98 | 20-24 | 1984-1990 |
| 3 Liter | 130 | 3.0/181 | 4 | 1.98 | 20-24 | 1984-1990 |
| 165 | 165 | 3.7/224 | 4 | 1.84 | 17-19 | 1984-1990 |
| 175 | 175 | 4.3/262 | 6 | 1.84 | 17-19 | 1984-1990 |
| 180, 190, 470 | 180 | 3.7/224 | 4 | 1.84 | 17-19 | 1984-1990 |
| 200 | 200 | 5.0/305 | 8 | 1.65 | 24-24 | 1984-1990 |
| 205 | 205 | 4.3/262 | 6 | 1.84 | 17-19 | 1984-1990 |
| 230 | 230 | 5.0/305 | 8 | 1.5 | 20-22 | 1984-1990 |
| 260 | 260 | 5.7/350 | 8 | 1.5 | 20-22 | 1984-1990 |
| 350 Magnum | 270 | 5.7/350 | 8 | 1.5 | 20-22 | 1984-1990 |
Mercruiser Alpha 1 Gen 2 (1991 & Newer)
| Engine | HP | Liters/CID | Cylinders | Gear Ratio | Tooth Count | Year |
|---|
| 3 Liter | 130 | 3.0/181 | 4 | 2.0 | 24-24 | 1998-2005 |
| 3 Liter | 130 | 3.0/181 | 4 | 1.94 | 20-24 | 1991-2005 |
| 4.3 Liter | 175 | 4.3/262 | 6 | 1.81 | 17-19 | 1991-2005 |
| 5.0 Liter | 230 | 5.0/305 | 8 | 1.61 | 24-24 | 1991-2005 |
| 5.7 Liter | 260 | 5.7/350 | 8 | 1.47 | 20-22 | 1991-2005 |
Serial Number Mercruiser Engine
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Alpha One Serial Number Lookup
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