SE218 Replaces most Mercury 3.0L Lower Units (SN 1B504989 and below). Does not replace the Torque Master, Torque Master 2 or the Sport Master.

13 Spline one-piece drive shaft.

If you have an 8 Spline drive shaft, you will need to buy the stub shaft unit
and buy an upper driveshaft from an OE dealer.

25" 45-823901A 1

The SEI 218 gear cases are supplied with the correct water tube coupling for units with a serial number of OG438000 and higher. If your unit has a lower serial number, you will need to use your old water coupling or buy the correct part (SEI part number 96-116-12K).