Capt John wrote: Using more restrictive filters can
cause problems with your supply pump, or, even worse, cause the engine
to run lean. That will cause the engine to run hot and, over the long
run, cause all kinds of other problems.


Huh? Diesels do not run "lean". Hint, think about you control
power/speed in a diesel.

Cheers
Martin

In article , Martin Baxter
wrote:

Capt John wrote: Using more restrictive filters can
cause problems with your supply pump, or, even worse, cause the engine
to run lean. That will cause the engine to run hot and, over the long
run, cause all kinds of other problems.


Huh? Diesels do not run "lean". Hint, think about you control
power/speed in a diesel.

Cheers
Martin

Just one of a few of Capt. John's misconceptions......

And another thing, if you keep your tanks full, you miss out on the washing
action of boat rolling fuel around against the sides of tanks that are less
than half full which helps keep down the crud growing there.

All in all, from the standpoint of fuel quality, there is probably more
downside from keeping tanks full than using most of the stuff up and then
refilling.

--
Roger Long

On Nov 12, 2:46*pm, You wrote:
In article , Martin Baxter
wrote:

Capt John wrote: Using more restrictive filters can
cause problems with your supply pump, or, even worse, cause the engine
to run lean. That will cause the engine to run hot and, over the long
run, cause all kinds of other problems.

Huh? Diesels do not run "lean". *Hint, think about you control
power/speed in a diesel.

Cheers
Martin

Just one of a few of Capt. John's misconceptions......

You need to study up a little, try asking your engine manufacturer
about those filters. The marine specialist at HO Penn, our local Cat
dealer on Long Island, was adamant about this. Said regardless of the
engine manufacturer, they specify the 30 micron filters for a reason.
Your probably more likely to get away with it with a little sail boat
engine than a larger high output engine. For the price of a rebuild,
or replacement, I'll take the manufacturers advice over your's and day
of the week.

"Capt John" wrote

You need to study up a little, try asking your engine manufacturer
about those filters. The marine specialist at HO Penn, our local Cat
dealer on Long Island, was adamant about this. Said regardless of the
engine manufacturer, they specify the 30 micron filters for a reason.

My experience with manufacturers and reps is that they will often give the
advice that is best for them and not the customer.
There was a big controversy going on about mixture control on aircraft when
I left flying. The mixture is adjusted constantly on general aviation
engines and the engine manufacturers were still giving the advice that put
the most stress on the engines, minimized their life, and fouled up the
cylinders the most with ash. Why? Because running the engines the way that
was best for the individual owner meant that everything about the engine had
to be nearly perfect. A slight induction leak or otherwise minor problem
would make the engine rough. If they advised people to run the engines
properly, they would be plagued with people coming back and complaining that
their engine was rough. So, they told them to run them the way that made
the engines the most tolerant even though they burned more fuel and didn't
last as long. It was more important to them that their engines have a
reputation for being smooth and trouble free than that the be economical on
fuel and last longer. Not strictly applicable to this but just to point out
that you should take info like Penn's with a grain of salt, even in aviation
where people die when the engine quites. Running the engine in my plane
properly also alerted me when a small problem like a loosening clamp on an
induction hose was developing and we could have it tracked down and fixed.

Your probably more likely to get away with it with a little sail boat
engine than a larger high output engine. For the price of a rebuild,
or replacement, I'll take the manufacturers advice over your's and day
of the week.

What is it between 2mu and 30 mu in size that is vital for the engine to
digest or else it will become unservicable?

There is usually a filter mounted on the engine that is part of the engine
and came as standard equipment. The flow and pressure drops of this filter
MAY have little enough margin and tolerance for what the engine mounted fuel
pump can handle that putting in an element that MIGHT be more restrictive
could cause problems for the engine mounted fuel pump. If this could occure
in a few cases, reps like HO Penn will translate it into gospel.

We're talking here about the filters upstream in the system which are part
of the fuel system; not the engine. These are usually accompanied by
separate feed or boost pumps or day tanks that put a pressure head on the
system. If you are delivering fuel to the engine mounted fuel pump at
pressure, as on my boat, it can't possibly matter what filter element is in
the primary filter.

I use the engine maufacturer supplied and recommended element in the filter
that is on the engine and painted the same color because it came with the
engine and there isn't much choice anyway.

--
Roger Long

On Fri, 14 Nov 2008 13:48:49 -0500, "Roger Long"
wrote:

The mixture is adjusted constantly on general aviation
engines and the engine manufacturers were still giving the advice that put
the most stress on the engines, minimized their life, and fouled up the
cylinders the most with ash. Why? Because running the engines the way that
was best for the individual owner meant that everything about the engine had
to be nearly perfect. ...

It's interesting to notice how much LONGER auto engines seem to be
lasting these days. This is not just that a made in Japan or Korea
engine is somehow better - but rather that all engines have engine
controllers any more, with port fuel injection as likely as not, and
adjust themselves on the run, to stay optimally lean and correctly
timed.
So they stay clean, and listen for ping, and sniff for stochiometry,
sometimes with two O2 sensors.
Too few aero recips are doing that. Porshe's try fizzled for instance.
The market is small.

BrianW

On Nov 12, 12:59*pm, Martin Baxter wrote:
Capt John wrote: Using more restrictive filters can
cause problems with your supply pump, or, even worse, cause the engine
to run lean. That will cause the engine to run hot and, over the long
run, cause all kinds of other problems.

Huh? Diesels do not run "lean". *Hint, think about you control
power/speed in a diesel.

Cheers
Martin

Wrong, wrong, wrong. You can run a diesel lean, when you have a
restricted fuel system, like your filters are clogged, it's starving
for fuel. Dead give away, the exhaust temperature starts to rise. If
you've got pyromiters you can see it right away. I've got Cats in my
boat, I don't need to look at the fliters to tell their clogging, the
engine temperature starts to rise. Change out the filters, and it
drops back to normal.

On Fri, 14 Nov 2008 09:19:59 -0800 (PST), Capt John
wrote:

rong, wrong, wrong. You can run a diesel lean, when you have a
restricted fuel system

Lean or rich describes fuel air mixtures, and Diesels don't even have
them.
Even so, lean lowers the temp.So does rich. Airplanes have a mixture
control and if you have an EGT gauge, it is easy to see it in action.
Lower temperatures on both the rich and lean sides of a peak. Lean,
you have less fuel heating the same ammount of air. This raises the
temperature how? It doesn't.

Casady