Wilbur Hubbard wrote:

"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
What auxiliaries do you have in your Swan 68 and Allied 32 footer? Just
curious.
--AG

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

"RW Salnick" wrote

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,

Good point for the general populous. I forgot that I was predicting the
behavior of my system with the Yamaha peculiarity (at least on the QM
series) of there being no return line to the tank. Return fuel is pumped
back around to ahead of the injector pump so there is no way to suck air
back into the system unless there is a leak in the piping.

--
Roger Long

On Mon, 13 Aug 2007 11:52:23 -0400, "Roger Long"
wrote:

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.


A guy in Singapore who used four or five filters moving his new (to
him) boat about ten miles from Raffels marina to the Republic of
Singapore club spent several days washing out his tank and then added
some stuff called "soltron". I think it is the same stuff except sold
in the U.K. He got much the same effect, fine deposits in the filter
bowl. It lasted for some time, as I remember. He had vacuum gages on
his filters and said that the filters didn't seem to be clogging, just
this "stuff" in the filter bowls.


Bruce in Bangkok
(brucepaigeATgmailDOTcom)

On Mon, 13 Aug 2007 16:48:33 -0400, "Roger Long"
wrote:

Good point for the general populous. I forgot that I was predicting the
behavior of my system with the Yamaha peculiarity (at least on the QM
series) of there being no return line to the tank. Return fuel is pumped
back around to ahead of the injector pump so there is no way to suck air
back into the system unless there is a leak in the piping.

Just following up on your "heeling 20 degrees comment": Athough true,
it is not nearly as vigorous as a day or two of bounding through some
serious waves. That will dislodge a lot more tank sediment than
normal heeling and tacking.

On 2007-08-12 08:20:15 -0400, "Roger Long" said:

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?

We had it happen once, just after we filled up the first time for the
season, about July. Seems there was lots of junk on the tank sides and
we were using the finest Racor filters. Engine started losing revs; got
a few seconds if I advanced the throttle, but then it died.

Changed the filter and cleaned out what I could, but the second clogged
in a couple of minutes' full power.

Not having a third filter (then) I brushed off the filter, cleaned the
bowl, and tried at reduced throttle. We could pull maybe 2000 (out of
3600) but that was enough to limp along at 4-5 knots to a "must"
rendezvous about 50 nm away. After those hours, we found out that we
could pull full power, and the primary (on the engine) filter was still
clear. We now carry a "coarse" filter as a third backup.

Oh, and I'm sure you realize that a dirty prop can drop the revs
significantly, so do your high-speed tests after you've powered for a
bit after a week or two away.

--
Jere Lull
Tanzer 28 #4 out of Tolchester, MD
Xan's new pages: http://web.mac.com/jerelull/iWeb/Xan/
Our BVI pages: http://homepage.mac.com/jerelull/BVI/

That is consistent with what I'm seeing using StarTron (repackaged Soltron).
There is stuff that seems to be coating and sticking to the bottom of the
sediment bowl but the fuel in the top of the bowl is clear and the engine
runs fine at max RPM.

I pulled the filter yesterday and it looks good. I know this doesn't mean
much but there was no corresponding build up.

I went to the Racor dealer yesterday to buy a vacuum gauge but they were out
for the time being.

--
Roger Long