On 7 May 2006 11:38:43 -0700, "Skip Gundlach"
wrote:

As I work my way back from the bow (the bulkhead forward of the
saloon), being almost finished in there, my thoughts turn to what's
ahead (or behind/astern, as you prefer).

I succeeded in buying a second Racor on eBay, and two mounted 2-way
valves at a flea market, but would prefer to not have to reinvent the
wheel, as I'm sure there are many here who have done it already.

I considered an already-built dual system, a standard Racor part
number, but it was prohibitively expensive. Theirs, of course, has a
single valve which controls all functions, and a vacuum guage.

Can anyone point me to how to make two separate filters set up in
parallel with the least amount of fuss about it?

Basically you need a supply line going to the tank feeding both
filters through their own on/off ball valve. The output side to the
engine looks the same, again with each filter with having its own ball
valve (total of 4). This allows the Racors to be totally isolated
during a filter change, which in turn allows "hot swapping" a filter
while underway. A vacuum guage on the suction side (towards the
engine) is very important. Without that you will not have an accurate
baseline for knowing when to change filters. I like to change mine
before they get to 5 psi since the Racors will start passing
contamination on through at about that point.

I normally leave the input valves on both filters open, and turn off
the output valve for the Racor not in use. If I suspect that a filter
element is becoming clogged (higher vacuum guage reading), I will open
the output valve on the second filter to verify that pressure drops.
If so, I close both input and output valves on the clogged unit until
I'm ready to change out the element.

If you have a large tank, and the boat will be sitting idle for any
length of time, a fuel polishing system is highly desirable, and well
worth the expense for the extra valves and fuel pump. An additional
electric fuel pump that can be valved in and out is also useful for
repriming and bleeding the fuel system. These are small touches that
can do a lot for overall reliability and ease of maintenance.