Latest Version now availible on cults3d with water cooling connector, cooling sleeve for motor and steering nozzle. https://cults3d.com/en/various/water-jet-pump
The cooling sleeve fits motors with 40mm diameter. You will need 2 Orings 40X3mm then it will be a watertight fit over the motorhousing.
The motor I use is a 4074 type.
This one here is not fully completed,