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?

--
Roger Long

Roger,

I have had problems with clogged fuel filters a couple of times over the
years. Usually when I have not changed the filter at the beginning of the
season. You are right the first thing that happens is that the engine looses
power at higher rpm's but when you throttle back she runs OK.

I have installed a two filter switchable system with vacuum gauges that
works great. On a recent trip from Rockland straight to Nantucket the first
filter got clogged and I was able to switch to the second while underway
with no problem.

Ansley Sawyer
SV Pacem

On Aug 12, 7:20 am, "Roger Long" wrote:
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?

Might....do you feel lucky?

Filters are cheap and easy enough to replace to make it SOP when
heading offshore if you have any questions or doubts about your fuel
quality. With your set-up Roger, it will cost you 6 bucks and 5 min
work.

A vaccume gauge is a great investment in peace of mind if you have
dirty tanks. Just T off between the filter housing and injector pump.
Then you will know..and not be on a wing and a prayer when the sh*t
hits the fan.

Joe


--
Roger Long

On Sun, 12 Aug 2007 08:20:15 -0400, "Roger Long"
wrote:

In 38 years around boats with auxilliary engines, I've never actually
experienced a clogged fuel filter

Count your blessings. You've either been lucky or been only on
exceptionally well maintained boats.

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.


You don't always get much warning with a clogged filter. Sometimes
the engine will begin to run a bit rougher and/or skip a beat now and
then. Those are serious symptoms on a diesel and should be
investigated immediately. More often, especially with a small engine,
your first warning will be a momentary speed up followed by a shut
down. That's when you get to practice changing filters at sea and
bleeding the injectors while you are upside down in the engine
compartment. It is also a good test for sea sickness issues and your
ability to remove foul smells from the bilge.

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?

Not necessarily but it can't hurt. Without a vacuum guage your best
defense is to frequently monitor the sediment bowl on your Racor by
draining off a bit at the end of the day into a clear container. Shine
a light behind it and look for sediment particles and a water
separation layer at the bottom. If you are not getting much gunk in
the sediment bowl your tanks are clean and the filter should last
quite a while, probably a full season. If you are getting gunk in
the bowl you are at much higher risk and should first take steps to
get the tank cleaned up.

The risks are much higher in rough seas when the boat is rolling and
pitching. Extra vigilance is required in those circumstances because
the boat motion stirs up sediment in the bottom of the tank and a clog
can happen very quickly. I monitor my vacuum guages every hour in
conditions like that and I've seen a large filter go from almost no
back pressure to very high in that space of time. I've got large
tanks however and recirculate 40 to 50 gph.

The only time I've had serious issues with a small sailboat aux was
from failure to check the filter bowl after a long day's run. The
next day, back pressure in the Racor built up high enough to dislodge
the O-ring and much of the gunk ended up in the engine mounted
secondary which was not only a bear to change, but also difficult to
locate replacement filter elements. I spent the better part of a 2
week vacation at Marthas Vineyard locating replacement filters and
bleeding/rebleeding the injection system.

"Roger Long" wrote in message
...
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?

--
Roger Long



I've only had this happen once while offshore... in the Med actually. It was
finally traced to bad fuel. The symptoms were that it would not run
consistently, would sputter and die, and even eventually failed to start
(fortunately we were in port on Sardinia at that time). I repeatedly told
the skipper to change the filter, but he insisted that couldn't be the
problem, since he changed the filter before leaving Malta (a week before).
(FYI, he had several spares aboard.) He finally killed the starting battery
from trying to get it started, then switching to the house battery almost
killed that one. In the process, he bled and rebled the fuel line. Finally,
he found a diesel mechanic to come take a look, costing god-knows how much.
The mechanic changed the filter, rebled the line, and it started on the
first attempt. I didn't say a friggin word. Happened twice more before we
got to Mallorca, and the skipper changed the filters himself, with no help
from any of the crew. We just went on deck to avoid the fumes.

--
"j" ganz @@
www.sailnow.com

"Roger Long" wrote in news:46befafa$0$3109
:

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



Sounds like a winner. If the filter's clogged a little, it'll run but
not at full speed. It simply runs out of fuel, limiting RPM.

If you shove it up to WOT, it'll run a ways, then start slowing down as
the engine starves for fuel, the vacuum in the lines increasing. If it
continues to run wide open with that wonderful carbon cloud from shoving
too much fuel into too little air, that doesn't mean the filter's not
clogged. It only means the filter isn't clogged enough that it doesn't
get enough fuel to go WOT. It's a matter of how much they're clogged
up...(c;

Most all of this problem is very easy to eliminate....Fill the damned
tanks BEFORE you store the boat so it can't breathe in and out of the
tanks...just like an airplane pilot does. Full tanks don't breathe,
don't ingest and condense water on bare walls inside the tank. Full
tanks don't have water in them, so they don't have black algae growing
between the water and the fuel to clog up the filter. No magic Diesel-
Fuel-In-A-Bottle, at $12/pint, is necessary...at all! There's a diesel
car out front that's 34 years old. It has never seen a drop of BioBor or
whatever other magic potions Waste Marine sells to gullible boaters. It
has never had its fuel polished, either. It has had a new fuel filter
about every 5-8 years, when I feel guilty. None of them have ever needed
to be changed that I can see. The filters are of the finest felt blocks
I've ever seen. But, if I'm not going to drive her for a while, I FILL
THE TANKS FULL. This must be the reason I've never seen any water in the
separator or black algae. The car is parked on the riverfront of the
Ashley River, not in a dry climate, either.

"Caution - Contains Petroleum Distillates"......Diesel-Fuel-In-A-Can.

On Sun, 12 Aug 2007 08:20:15 -0400, "Roger Long"
wrote:

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?

There are two circumstances where you get clogged fuel filters. One,
you are running dirty fuel and the filter is doing its job and
filtering out all the little bit and pieces that come down the line.
In this case the symptoms are a loss in power.

The second case is where you have a substantial amount of water/sludge
in the tank and that suddenly gets into the fuel inlet. In this case
the engine stops right now!

The first case is pretty common where you are using dirty fuel, we ran
into it constantly working in the jungle where we were refueling from
drums. The fuel we were buying was probably not very clean and
dragging the refueling hoses around on the ground certainly didn't
help any either. The equipment operator would come in for lunch
bitching that "the damned thing doesn't have any power" and we'd go
out and change the filter.

The second case is catastrophic in that the entire fuel system from
the tank through to the injectors will be full of water/sludge. You'll
have to bleed the tank and fuel line all the way to the injector pump
and then disconnect the injector lines and motor over the engine until
you get clean fuel that through the injector lines and (invocations
to the Engine Gods help at this point) connect the injectors and hope
that you can get it to light off.

If you are getting "dirty" fuel there isn't much you can do except try
filtering it before you pump it into the tanks. The second case can
*usually* be overcome by draining the tank sump before starting the
engines.


Bruce in Bangkok
(brucepaigeATgmailDOTcom)

My neighbor, the fuel polisher, will tell you that you won't know you
have a developing problem until you hit some rough seas and stir up the
crap in the bottom of your tank.
Of course, then it's too late and at the worst time.
Gordon

That's true and fairly well known but it's a different problem.

Considering how promptly stuff started showing up in my filter bowl after I
started puting in StarTron, I think it must be doing a pretty good job of
moving the stuff into suspension and into the fuel intake. This is also a
sailboat the routinely heels 15 - 20 degrees so the tank gets pretty well
mixed. Thge slow build up from stuff moved into suspension is what I'm
concerned about tracking. You can't do much about the sudden clogs except
be ready to change filters in less than optimum conditions.

--
Roger Long

"Gordon" wrote in message
...
My neighbor, the fuel polisher, will tell you that you won't know
you have a developing problem until you hit some rough seas and stir
up the crap in the bottom of your tank.
Of course, then it's too late and at the worst time.
Gordon

Motor boat talk!

If the seas are rough it means there's wind. If there's wind you use
your sails and not your motor. I can always tell who the pretenders are
by their knowing that rough seas cause diesel problems because there's a
blender at work mixing all the crud at the bottom of the tank with the
fuel.

I've also noticed that diesel boat people have this motor = security
blanket syndrome. You see them, even at anchor, when the wind pipes up
on goes their motor. I think they have this idea they can motor forward
to reduce the tension on the rode. But, boy oh boy, why not just get
ground tackle you can depend on? Running the motor and taking it in and
out of gear might be the worst thing you can do during a blow because
the boat will then end up sideways to the wind and the pull on the
anchor jerks sideways with extra force. I often wonder how many anchors
get broken out that would have otherwise stayed put if only the diesel
was kept turned off.

This is but one example of deviant behavior engaged in by diesel boats.
In general diesels make sailors incompetent. The best sailor in the
world is a man who has no motor whatsoever on board.

Wilbur Hubbard