SEI SE428 Yamaha Counter-Rotation Lower Unit 30" ShaftThe SEI SE428 is an aftermarket counter-rotation replacement lower unit for select Yamaha V6 outboards with a 30-inch driveshaft configuration. Choose the 1.81:1 two-stroke version or the 2.00:1 four-stroke version to match your engine. Both feature left-hand rotation and a black finish that can be painted to match.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 for compatible port-side applications; 30-inch driveshaft configuration; Application-specific 1.81:1 or 2.00:1 gear ratio; Black finish; paint to match your engine if desired; Available Applications Two-Stroke V6 90-428-A30: For select Yamaha 3.1L and 3.2L V6 two-stroke 200, 225, and 250 HP applications requiring a 1.81:1 ratio. OE reference: 60W-45300-30-8D.; Four-Stroke V6 90-428-B30F: For select Yamaha LF225 V6 four-stroke applications requiring a 2.00:1 ratio. OE reference: 69K-45300-31-8D.; Additional Four-Stroke Replacement ReferencesSEI also lists Mercury references 1623-888680T09 and 1623-888680T5 for the 90-428-B30F only. Verify the exact application before ordering.Fitment and OrderingBoth versions are for counter rotation only. Do not use them for standard-rotation applications. Confirm your full engine model number, serial number, engine type, existing gearcase number, gear ratio, and shaft length against SEI's application guide before selecting an option. Horsepower alone does not confirm compatibility.