ESellSimpleTILT Trim Motor Compatible with Yamaha Outboard 40 50 60 70 90 HP 2-Wire 6H1-43880-02 10830

While motor seems to work o'k it came without the o-ring, which I was unaware I needed. Not a simple installation and of coarse it leaked. After searching YAMAHA schematics I discovered the o-ring. Had to search and find the o-ring. With all this and re-installing motor I lost a week. As I was sick the re-installation upset me the most. I suspect maybe motor was suposed to have o-ring already on it? I wonder maybe was this motor a re-turn? Will never know. May I either leaving o-ring in seperate package with packing slip showing the nedded o-ring, or something in description saying: product requires o-ring, included?