I purchase a 2003 Johnson 90 HP 2 stroke model J90PLSTC. There are two threaded ports at about 7 o'clock position on each of the top cylinders (see picture. I can't find any mention of these ports in the operator or service manual. I assume they may be for a water pressure connection but the operators manual shows this as being on the opposite side where the port is plugged. Are these perhaps optional positions for the water pressure pick-up. What should be connected to these ports? Do I really need the water pressure or can I just plug the ports. If I plug them, is it a standard pipe plug?
