In this project I have redesigned the water pump by hoankhoa0103 to fit the 775 Motor Externally. I haven't printed the body at 100% due to which I have leakage but printing at 100% infill is recommended.
https://youtu.be/clpkzcEFEZI
Technical
Layer height 0.2mm
Infill 30% you should print at 100%
Support material where needed
Print at a higher temperature for strength
bearing 696zz
Flexible shaft coupler 5x8mm
775 DC motor