Hi and welcome to the SeaDoo forum. I'm sure someone will be able to help you, but we probably need a little more information. Does your Challenger have one or two motors and what year is your boat, if you're not sure about the year it's the last two digits of the HIN (hull identification number).
We recently went on a southern Caribbean cruise and one of the stops was Bonaire, what a beautiful place. We did a little snorkeling at Playa Lechi and all I can say is WOW, I've been a lot of places but I have never seen snorkeling that good anywhere. We plan to come back to Bonaire as a destination and do some scuba diving.
This drawing shows how the cooling system on a SeaDoo 787 works, it may be of some help.
Lou