Onboard diesel polishing
see-through bowl and water drain;
with ¾ inch ports which required
two Racor hosetail ¾ to^3 ⁄ 8 in
connectors and also two^3 ⁄ 8 in to
10mm hose couplings.
One 12V fuel pump with^3 ⁄ 8 in
ports to which two^3 ⁄ 8 in to 10mm
hose couplings were fitted.
One tee piece with^3 ⁄ 8 in ports
to which two^3 ⁄ 8 in to 8mm and
one^3 ⁄ 8 in to 10mm hose couplings
were fitted.
One lever-handle ball valve with
(^3) ⁄ 8 in ports to which two (^3) ⁄ 8 in to
10mm hose couplings were fitted.
One tube of Hylomar universal
blue joint compound – which
was used on the threads of all
the couplings.
Two metres of 10mm flexible
fuel hosing along with eight
13-20mm Jubilee clips and two
9.5-12mm Jubilee clips.
First of all I had to site the new
fuel filter in the engine bay; I had
considered the alternative of
stowing it in the cockpit locker
adjacent to the fuel tank, but I
rejected that idea since the filter
would be exposed to damp and
damage from other items stowed
Tee connector into engine fuel spill line
Optional secondary supply to engine
Shut-off valve
Fuel tank
Engine
Racor
filter
Pump
Shut-off
valve
A simple schematic showing John’s fuel-polishing set-up
in the locker. The actual position
selected for the filter was quite
critical as space was needed
both above and below it in order
to change the filter from the top
and to drain it from underneath.
In all, I needed a space of about
20in (50cm) in height, and it
ideally needed to be neither below
the bottom nor above the top of
the tank to enable the pump to
provide a maximum flow rate. In
the end I moved the automatic
fire extinguisher along the
bulkhead in order to place the
filter in front of the engine, where
it was easy to get at, and clear
of any rotating components.
The filter works more efficiently
if it is upstream of the pump,
therefore the supply from the
bottom of the fuel tank sump was
fed by 10mm fuel hosing through
the bulkhead direct into the filter.
The outlet from the filter was
connected via a short length of
10mm hosing to the electric 120lt/
hour fuel pump. From the pump I
ran 10mm hosing to a convenient
place on the 8mm engine fuel
return spill line, which I cut and
reconnected using the tee piece
(with two 8mm and one 10mm
hose connections). I have also
fitted a stopcock between the tee
piece and the electric pump as
I did not want to risk a backflow
from the engine fuel return spill
line into the Racor filter when the
engine was running. I suspect that
I was worrying needlessly... but
it does give me the option to fit
another T connector and stopcock
from the electric pump direct to
the engine fuel supply line so that
I could swiftly swap fuel supply to
the engine. I had a spare circuit
breaker on my electrical panel,
so it was a simple task to run an
electrical supply cable behind the
wall furniture of the heads (using
my trusty GRP cable ‘puller’ rods)
into the engine bay to the pump.
Once a fortnight
Having finished the installation,
I can now polish the fuel once a
fortnight throughout the winter
even though the boat is laid up
ashore – and, of course, as
necessary during the season. The
cost was about £200, so I would
need to save a lot of fuel before it
has paid for itself; but at least I’ll
sleep easier. As a retired aviator,
I have this dread of the sudden
sound of silence – especially as,
in my experience, it has the
habit of happening at the
most inopportune moment!
LEFT The fuel pump supplies polished fuel back
to the tank through the stopcock to the tee
connector in the spill return line. Below is the
in-line 30-micron filter that feeds tank fuel to
the engine
BELOW The Racor 500FG turbine fuel filter is
sited in front of the engine to enable easy
access for servicing