Roger Long brought forth on stone tablets:
In 38 years around boats with auxilliary engines, I've never actually
experienced a clogged fuel filter so I'm curious what the first signs are,
at least for slow build up as opposed to the fuel line suddenly sucking up a
mess that's been kicking around in the bottom of the tank.

I would expect that slowly developing problems would first show up at
maximum RPM and fuel flow and that the engine would continue to run properly
for a time at lower power. If I make it a practice to bring my engine up to
full RPM at least once during every run, I should first see a failure to
reach the usual number, perhaps accompanied by some smoke due to the
injectors not getting enough fuel for the rack setting. Backing off to my
usual cruising fuel flow, which is about 60% of WOT, should give me plenty
of running time to get to a place where I can safely change the filter.

Next year, I'll put in a vacuum gauge but, in the meantime, will this
strategy work?


On Eolian, a developing filter blockage doesn't manifest itself until
the lift pump cannot deliver sufficient fuel to the injection pump. At
that point, the injection pump begins to suck air from the return line,
and the engine starts stumbling. Going into neutral and reducing the
throttle helps a little, and may save a bleeding exercise. but not
always. If I can get down below and switch filters in time, then the
engine can ingest a little air and correct itself. If not, well time to
get out the 10 mm wrench...

Get the vacuum gage and install it where you can see it without having
to pull up a floor panel. That's your best monitor of filter condition
and impending problems.

I don't think your planned strategy will work. But if you perform it at
the dock, you may get to do the bleeding exercise at the dock instead of
out in a seaway, while being carried by a strong current toward a shoal.

bob
s/v Eolian
Seattle