Our Upper & Lower 1.47 Ratio Sterndrive alpha one generation 1 Upper & Lower Unit SEI-106 (SEI-147 Outdrive, 1.47 Ratio Mercruiser sterndrives alpha one generation 1) are the highest aftermarket quality products you will find anywhere across America. Note that our products are not rebuilt; they are simply available at the lowest prices you can find.
This unit is a Replacement for (Mercruiser’s R/MR/Alpha One 1/O 1972-1990) Standard Rotation or Counter Rotation 1.47 Ratio
- 228 HP and up from 1974-1990.
- 225 HP-S 1974
- 233 HP1975-1977
- 250 HP 1977
- 260 HP 1978-1982
- 898/228 HP 1977-1982
- R/MR/Alpha One 1983-1990
- Engines from 1983-1990 include 5.7L, 5.0L (4 barrel carb)
- Engines from 1983-1990 include 350, 305 (4 barrel carb)
- Engines horsepower 260 HP, 230 HP, 228 HP
- Replaces most Mercruiser Sterndrives from 120-260 HP 1967-1990
- You must have trim and tilt to be able to use our replacement drive.
- You must know if you have counter rotation unit on your twin engine boat, look at the propellers to see if they are identical , if they are they are both standard rotation. If the propeller blades are opposite, then the port side should be counter rotation.
- If your unit has a short yoke 8 inches and 1/8 on the upper driveshaft, it is a ”Old Style”. Old Style are on all inline 4-cylinders and inline 6-cylinders and up to including 1982.
- You must have trim and tilt for replacement to work. If it has tow trim hoses going to each cylinders it has trim and tilt.
- Unit has an eyelet on top cover replacement cover utilizes the new style flat top.
- How to Identify Sterndrive alpha one generation 1, on trim cylinder uses large rubber bushings and large washers and nut generation II uses small plastic bushing and small e-clips.
- How to Identify Sterndrive alpha one generation 1, The top cover square shaped generation II more rectangular.
- How to Identify Sterndrive alpha one generation 1, water pump housing is plastic generation II Metal.
- To get gear ratio, it is best to remove the top cover and count the teeth on the upper gears.
Ratio 1.94 / 20-24 teeth
Ratio 1.81 / 17-19 teeth
Ratio 1.62 / 24-24 teeth
Ratio 1.47 / 20-22 teeth
This unit comes with a 9-9/16 new style input yoke.
Install Kit or Anode Kit not include.
Warranty is not covered over 300 HP.