Well, Joe, that certainly establishes you as our resident filter expert. I
believe you 100%. Now that it's clear that we are having an informed and
intelligent discussion, let me get more precise and specific to my
situation.

"Joe" wrote A vortex is made in the bowl that
helps seperate the water from the
fuel.

This is clear from the design of the filter housing. The key word in your
statement is "helps". The issue is how much the help is. If it is 80% -
90%, you could say that the separator is essentially worthless at low flow
rates. If it is something like 10% it is not going to be critical in most
applications were simple gravity driven separation will do a lot of the
work.

Running crew boats with their notoriously wet fuel (that I've heard about
from others), wringing maximum performance out of the filters could be a
significant operational consideration. At best, you might still be wishing
the filters were doing a better job. That last 10% of performance might be
quite noticable.

I saw no hint of water or other contamination for two seasons. Considering
how little attention most boaters up here pay to the subject (just saying,
"do whatever it need" to the yard once a year), and how few I see being
towed in, it's probably typical for this climate and fuel infrastructure.

When I look at the smallest filter housing, I see that it is rated for 15
GPH. Scaling it down to preserve the same flow dynamics at the less than 1
GPH I'm usually drawing would make it so small that the filter wouldn't last
long. It would have to be a completely different design, a swirl separator,
a separate chamber for water to collect, and a larger filter housing.

I'm not likely to get "swirl boost" out of stock Racors anyway at flow rates
less than 1/15 th of maximum. The simple gravity separation will be more
effective in a larger volume and slower flow, that's why some vessels use
day and even separator tanks. A larger filter will last longer. That's why
I don't see a downside to larger filters in my fairly common situation.

For a crewboat, or a yacht picking up lots of third world fuel in a similar
climate, no doubt in my mind that you are spot on about the proper sizing.

The jury is out for me on additives. A yard manager with a lot of
credibility told me not to put anything in my fuel so I didn't for two
years. Then, I had just a few hiccups in an otherwise smooth running engine
with a nearly empty tank and began to find alge in the filter bowl. I put
in the StarTon and the bowl filled up with green stuff and the filter turned
green black although the engine ran fine. One tank of fuel after the filter
change, the bowl is clear. It certainly looks as if stuff was flushed out
of the tank that would otherwise be building up. Keeping it moving through
to the filter in smaller amounts instead of building up so that a big glob
gets sucked up in rough seas, which is when it invariably happens, seems
like a good idea.

--
Roger Long

I wonder also if this flow issue factors into the filter size debate that
has gone on here an other places. 2 micron filters would reduce the flow
rate and thus the effectiveness of the water separation. In a situation
where you were just barely getting enough water out of the fuel, passing
some particles on the the secondary filter(s) might be important. Also, if
filters are operating close to maximum flow, they won't be able to hold as
much before needing replacement. Secondary filters, which are not also
called on to separate water, would then be the best place to deal with the
finer particles.

In a situation like mine, where water is an insignificant problem, the
smallest filter I can buy is way oversize for the optimum flow rate, and the
secondary is a real bitch to change out, continuing to run 2 micron elements
in the primary makes sense to me.

What do you think, Joe?

--
Roger Long

On Jul 30, 10:23 am, "Roger Long" wrote:
I wonder also if this flow issue factors into the filter size debate that
has gone on here an other places. 2 micron filters would reduce the flow
rate and thus the effectiveness of the water separation. In a situation
where you were just barely getting enough water out of the fuel, passing
some particles on the the secondary filter(s) might be important. Also, if
filters are operating close to maximum flow, they won't be able to hold as
much before needing replacement. Secondary filters, which are not also
called on to separate water, would then be the best place to deal with the
finer particles.

In a situation like mine, where water is an insignificant problem, the
smallest filter I can buy is way oversize for the optimum flow rate, and the
secondary is a real bitch to change out, continuing to run 2 micron elements
in the primary makes sense to me.

What do you think, Joe?

--
Roger Long

Seems your additive is making the alge smaller, and water particles
smaller, so I'd stick with finer filters. The alge growth is not
effected much by water in the fuel. Your problem is due to fuel
sitting to long in the tank and degrading. Todays diesel is far more
unstable than it was 15-20 years ago due to all the catalytic cracking
to squeeze more out of a barrel of crude.

What we call alge is really tar and wax ect..ect..seperating from the
light oil and forming globs. Best thing you can do is use your fuel up
asap, or install a polishing system.

I'd suggest lots of motor sailing for you.. and a 12 pack of filters.

Joe

On Mon, 30 Jul 2007 07:58:05 -0400, "Roger Long"
wrote:

The jury is out for me on additives. A yard manager with a lot of
credibility told me not to put anything in my fuel so I didn't for two
years. Then, I had just a few hiccups in an otherwise smooth running engine
with a nearly empty tank and began to find alge in the filter bowl. I put
in the StarTon and the bowl filled up with green stuff and the filter turned
green black although the engine ran fine. One tank of fuel after the filter
change, the bowl is clear. It certainly looks as if stuff was flushed out
of the tank that would otherwise be building up. Keeping it moving through
to the filter in smaller amounts instead of building up so that a big glob
gets sucked up in rough seas, which is when it invariably happens, seems
like a good idea.

Fuel isues on a commercial boat are very different than pleasure
craft. Commercial boats are in use almost every day, rarely sitting
around idle for any length of time. They are constantly taking on
fresh fuel with very high turnover rates.

Pleasure craft are almost totally the opposite with infrequent usage
for the most part. As a result fuel sits around in the tank for long
periods of time and even trace amounts of moisture become a breeding
ground for diesel bugs. Check the archives of the "Trawlers and
Trawlering" (T & T) mailing list. Fuel conditioning, fuel polishing
and filtration are *very* hot topics.

Google search -- site:samurai.com fuel filters

or fuel polishing, fuel conditioning, etc.

http://www.google.com/search?hl=en&q...=Google+Search