Not so !!!!!!!!!!!!

The filter media of fuel filters is a mixture of cellulosic fibers and
a 'wet-strength' resin. Although the 'aim' of the technical resinated
paper manufacturer is to have the resin coat all the fiber surface
inevitably there will be some fiber sites that are not resinated.

Here comes the 'important' part: Cellulose decomposes in the presence
of water over the long term ... think of how toilet paper (a cellulosic
papear) falls apart a short time after 'wetting'.
Sooooooooo, if you are using the typical resinated papaer filter
elements (Racor, etc.) AND you have noticed free water in the sump of
your filter .... then increase your normal changeout schedule OR keep a
record of the differential operating pressure of the filter at near
engine wide-open-throttle (WOT) ---- as a filter that is 'breaking
through or has cellulose that is now softening/digesting will show a
REDUCED pressure differential as previous under you 'reference' engine
rpm.

Secondly, such filters are pleated, the diaphragm pump is a 'pulse
type' pump and the pleates in the filter 'flex'. Under long term
flexing of the pleats, the media will break and the filter will
'unload' its retentate down stream ..... ; thus, keep an eye on the
pressure gages and change out frequently if you notice a non-linear
increase in differential pressure in the filter immediately down
stream. Simple recommendation ... if you use the engine a lot consider
changing every 100 or so hours of operation with respect to pleat
breakage by flexure; or, keep a damn good eye on the filter gages.

:-)


I'm thinking that filter changes, in the absence of picking up some problem
fuel, should be a function of the total amount of fuel that flows through
the filter and not an automatic once a year thing. I'd like to know what
experience other sailboat owners have had, recognizing that hotter climates
and fuel from funkier places than Portland, Maine might dictate more
frequent changes.

--

Roger Long