Dene wrote:

Poured water into it with the valve near the toilet set to the left (right
is to flush it). Water slowly drained in that position. Is that normal?

Yep...marine toilets aren't designed to hold water in the bowl...so
unless the discharge line goes uphill, any water in the bowl will drain.

I think the problem has to do with unit being above the waterline.

Nope...above or below the waterline has nothing to do with whether a
toilet can prime or not.

The
previous owner closed the seacock and consequently, it will not prime unless
I install a loop.

Nope...the problem is in the PUMP.

A loop has nothing to do with whether the toilet can prime or not. It
may pump whatever water is left in the line between the pump and the top
of the loop, but if it can't actually prime and continue to pull in
water, it'll "lose prime" as soon as that water is gone.

The PO was right to close the seacock. ALL seacocks should always be
left closed when no one is aboard. Open seacocks are the leading cause
of boats sinking in their slips. Closing it has nothing to do with
whether the pump can reprime or not.


I may just dump the Jabsco and go with the Raritan. I
can get one for $225 locally. Until then, I'll just pour water into it as
needed.

Now THAT's a plan!

Meanwhile, at the risk of being perceived as trying to sell you
something, if you'd like to learn what causes most "headaches" and how
to cure--or better yet, prevent--'em, you might want to check out the
link in my signature.


--
Peggie
----------
Peggie Hall
Specializing in marine sanitation since 1987
Author "Get Rid of Boat Odors - A Guide To Marine Sanitation Systems and
Other Sources of Aggravation and Odor"
http://shop.sailboatowners.com/books...ku=90&cat=1304