I replied to this thread in the other forum, but will post it here as well, since the other forum was not a Carver forum:
The fittings on my 1995 Carver are Flair-It, and Pex tubing and look like this:
A close up of the Flair-it fittings look like these:
If yours looks like the same thing, the tubing is interchangeable with the Watts brand fittings available at Lowes - at least all of the Lowes stores in my area. Ace Hardware sometimes carries both Flair-it and Watts.
I was having issues with leaking fittings so I replaced the plumbing in this area last year with Watts Pex Quick-Connect fittings. So far, no problems.
The only issue is that the Flair-it fittings damage the Pex tubing, so you will have to trim back the tubing or replace it when you want to use the Watts fittings. Pex Tubing is also available at Lowes and will also fit both Flair-it and Watts fittings.
Another brand that is similar, but not interchangeable is the system by Whale systems. These are found on Four Winns boats (at least on the boat I had). Unfortunately, the Whale fittings are metric and won't work with the 1/2" fittings on my Carver.
If you cannot find the Watts fittings at your local Lowes, go to Amazon and search on "Watts Quick Connect". You'll find both fittings and tubing there. You will want to verify the size, but on my boat, they were 1/2" fittings, if I recall.