this is a simple model with a gardena to m8 x1.25 thread some older outboards like the 30ae and 30am have a flush port (it looks like and oil fill screw but its higher) review your owners manual for details if you have a flush port this is made for running above water (be sure to tie down the motor as the printed part is quite fragile at the thread section) ive made it a bit long on purpose so you can use a pair of pliers to snap a bit off if necisary but it should just screw in 

(edit as you like in the slicer or remix entirely)

print settings:

quality: 0.20mm

supports: Yes

material:pla/abs/nylon (basically needs to be strong)