Mercury Outboard 6 8 9.9 15 HP 2 Stroke Long Shaft Lower Unit Gearcase 1666-8833T15
The oil was free of water when drained and the unit passed a pressure test of 15 psi (20 minutes).
The driveshaft is 23 1/4" from top of gear housing to end of the driveshaft. The driveshaft has 10 splines.
The prop shaft has 8 splines.
The water pump impeller was not inspected and should be replaced before use.
You will need to fill the unit with fresh gear oil prior to use.