prevent the engine from starting, but is there any rule (ABYC or
otherwise) or reason not to put in such a valve?

Our boat (1973 GB36 w/ FL120s) was fitted with an entire new fuel system
by the previous owner the year before we bought the boat.  New tanks,
new tank layout, new fuel plumbing.  There is a valve in each fuel
return line that directs the return fuel to one of two tanks.  This
valve does not have an OFF position, only the two tank positions.  So
there is no problem with putting a valve in the fuel return line between
the engine and the tanks.  Whether or not this valve can include an OFF
position is another question, however.  I would think you could get the
answer pretty easily from a qualified surveyor or diesels shop.

C. Marin Faure
GB36-403 "La Perouse"
Bellingham, Washington

There is no problem with having a shutoff in the return line... unless
you leave it in the off position when attempting to run the engine. How
you prevent that from EVER happening is the tricky part.

The valve could get closed by brushing up against it while inspecting or
working in the engine room, could happen without your knowing it. Any
such valve if installed should be wire tied so that it can't be closed.
Same for any relief valve in the hydraulic steering system, tied in the
normal position. Comes under the heading of: been there...

Then there was the engine where the installers hooked the return lines
and feed lines up backwards. Of course the engine can't run that way. Of
course, the "engine" didn't know that, so it ran anyway while it blew
the seals out of the fuel pump.

Mike

Capt. Mike Maurice
Tigard, Oregon (Near Portland).

Mike Maurice mikem@yachtsdelivered.com writes:

I faced the exact same problem on Island Eagle. My fuel return lines are
about 8" below the top of the tank, and if I ever needed to work on the
return lines with the tanks full I'll need the ability to close them off. So,
I installed two ball valves right at the tank. Then I made sure that they
were both open. Then I put a big label saying "These valves to be left open
at all times". And then (here's the important part) I removed the handles and
put on on a hook in the engine room. Voila. If I really need to turn off the
return, I grab a handle, slip it over the valve stem, and turn it off. The
rest of the time, the valves are open because there's no way to close them.

Scott Welch
Product Manager, Open Text Collaboration and Social Media Group
www.opentext.com
905 762 6101

"Things turn out best for people who make the best of the way things turn
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