SEI SE318 Johnson Evinrude Magnum Counter-Rotation Lower Unit 1.85:1The SEI 90-318-A SE318 is an aftermarket counter-rotation replacement lower unit for select Johnson and Evinrude outboards equipped with Magnum or Magnum II gearcases. Featuring a 1.85:1 gear ratio and black finish, it replaces OE number 5007670. Original Magnum applications require removal of the new lower unit's alignment pins.This item is subject to a 20% restocking fee.Year, serial number, and horsepower are required to process your order. Please contact us with this information after placing your order. Processing will be delayed until this information is received.Features Counter-rotation configuration; 1.85:1 gear ratio; Replacement for compatible Magnum and Magnum II gearcases; Black finish; Fitment and Installation Magnum II: Direct replacement for compatible applications.; Original Magnum: Remove the alignment pins from the new lower unit before installation.; Upper driveshaft, shift shaft, water pump, and water intake screens are not included.3.4L Water Pump RequirementsSEI identifies OEM water pump kit 5007972 for 3.4L engines. SEI kit 90-306-01K requires modifications; consult SEI's installation guidance before using it.OE Replacement Reference5007670.Confirm your exact engine model, serial number, existing gearcase, rotation, and upper driveshaft requirements against SEI's application guide before ordering. Gear ratio alone does not confirm compatibility.