One of the most common problems with diesel powered boats is gunk in the
fuel.... this is a fault of diesel's virtue of being so economical that
fuel sits around for a long time getting gunked up... gasoline engines
suck up their fuel too fast for this to happen

Anyway our boat had a RACOR 900FG filter when we bought it, installed in
a not-too-great location on the aft bulkhead of the engine room. It was
accessible, but only by climbing over the engine. Not a good scenario
for clearing a filter underway. Also, there was no way to install a
parallel filter for easy switching. No vacuum gage.

I also talked to a lot of diesel experts about the filter size. This is
a 90 gallon per hour filter, and our engine pulls in about 7 or 8 gph
max (it does not recirc much fuel). This means that the turbine water
seperator was not getting enough flow to spin the fuel, no centrifuge
effect. The extra large bowl might help water settle out, but never
showed any water.

So I am doing a couple of things
1- replacing the R-900FG with a 500/75 twin filter, rated at 60 gph in a
parallel mount with a vacuum gage. We are planning to use 2 micron
filter elements.

2- increasing the suction piping to 1/2" OD tubing.

3- installing the new filter assembly right below an access door cut in
the aft ladderway, so that the filters can be reached without entering
the engineroom much less climbing over the engine itself.

4- installing suction & supply manifolds so that either tank can be
selected and any of the diesel fueled equipment (engine, genset, heater)
can be cut in or out of the fuel loop.

5- provision for a polishing pump to be installed at a later date. One
of the tidbits I learned was the a polishing pump discharge should NOT
be piped into the engine recirc line. Backpressure to the injector pump
(even a tiny bit) is bad. So bad that a check valve is not going to do
the job. This may be different on different engines.

Right now the job is about 3/4 done and I have all the tools and parts
to finish it up... makes me nervous to have the fuel system
disassembled. So maybe this coming weekend we will be able to get
underway again!

Fair Skies
Doug King