[C320-list] Fuel filter bleeding

[Steve Magennis]

Jeff:
Yanmar doesn't ship any engines with a Racor primary filter.  They ship
their engines with the recommended (and strongly recommended by all
competent mechanics) 2 micron SECONDARY filter.  This diecussion is
about the Primary  RACOR filter.   The filter in the RACOR filter (the
first one that the fuel sees after it leaves the fuel tank) should be
30 microns.  That way the majority of gunk gets removed before the fuel
hits the lower capacity, finer mesh size secondary filter immediately
before the critical mechanical parts (like the high pressure pump and
the fuel injectors)

You won't do anything bad to the engine if you use too fine a primary
filter, but the filtration capacity of a finer filter is lower than
that of a coarser filter, so you will need to change your primary
filter more often (which won't be a problem unless the filter gets
plugged and your engine won't run for lack of fuel just as you are
trying to enter a tricky harbour at night with a storm brewing ....).

In the chemical industry, it is very common to put a fairly coarse
filter ahead of a fine polishing filter to increase the filtration
capacity of the system.  It is extremely unlikely that sequential
filters of the same micron rating would be used in any chemical
process, and at my previous job at a pharmaceutical plant, we typically
used a 33" diameter by 4 foot tall 40 micron filter backed up by a 2"
by 10" 2.5 micron secondary (or polishing filter).  With the primary
filter, we would typically remove 50 - 100 lbs of very fine  material,
and we would never need to change the secondary filter (neither would
there by much in the line of fine particulates in the final product).

Steve
Alchemist C-30T #4764 (Formerly)
Alchemist C-320 #909 (Formerly)
Alchemist C-380 #71 (Currently)

--- Jeffrey Hare <Catalina at thehares.com> wrote:

> Well, I guess the best logical explanation we seem to be getting here
> is "my
> guy says so" which doesn't do much to appease the engineer in me. :) 
> 
> 
> Perhaps we should find another person at the Yanmar factory and ask
> them
> too.  The Yanmar factory guy we asked last year at the C320 regatta
> said
> Yanmar switched to using 2 micron filters.  10 years ago they
> probably WERE
> installing 10 or 15 micron filtration systems on the engine.  I don't
> question whether our local diesel goddesses are capable and amazing
> mechanics, just whether they are fully current with Yanmar's current
> recommendations? 
> 
> I guess since Yanmar factory ships our engines today with 2 (or 3?)
> micron
> engine filters installed, that tells me anyway that they want 2
> micron
> filtration protection for their injectors. I guess however you get
> that
> level of filtration, by the time the fuel gets to the injectors, is
> probably
> just fine.
> 
> Here's the reasoning I'm following anyway:
> =========================================
> Since the engine mounted filter is so physically small and has so
> little
> filtration surface area, that I just consider it a "last chance"
> filter.
> It'll clog pretty quickly if I get really bad fuel or stir up the
> gunk on
> the bottom of the tank.  If I use the large surface area of the Racor
> as my
> main filter and separator, I'll never have to change the engine
> filter in an
> emergency, just the primary. 
> 
> If you think about it, if you get dirty fuel, it's going to have more
> suspended fine material than big stuff, so the big stuff probably
> won't clog
> the larger Racor before the fine material clogs the engine mounted
> filter.
> My goal was to avoid ever having to change both filters underway if I
> got a
> clog.  The engine is going to be HOT and changing the engine mounted
> filter
> in rolling seas on a hot engine isn't my idea of joy. I'd rather just
> quickly change the Racor, bleed a little air from the secondary and
> be back
> topside as quick as possible (retaining my lunch preferably). :)
> 
> All that said, I have a single 2micron filter on my tractor's yanmar
> diesel
> engine fuel line that's about the same size as our 3GM engine filter.
> It
> hasn't clogged up in almost 9 years (550 very dusty engine hours). 
> So, in
> the end, maybe it's not that critical.  (Hmm... Maybe it's time to
> change
> that one...)
> 
> Good luck with whatever choices you make!
> 
> Cheers!
> -Jeff
> 
> -----Original Message-----
> From: c320-list-bounces at catalina320.com
> [mailto:c320-list-bounces at catalina320.com] On Behalf Of Kurt
> Budelmann
> Sent: Friday, August 31, 2007 9:57 AM
> To: C320-List
> Subject: Re: [C320-list] Fuel filter bleeding
> 
> FWIW, my Yanmar dealer, Inland Marine Diesel recommended against
> using the 2
> 
> micron primary filter and instead recommended the 30 micron filter,
> R15p.
> 
> __
> Kurt Budelmann
> Everwind, Catalina 320, #1035
> 
> 
> ----- Original Message ----- 
> From: "Scott Thompson" <sthompson at toad.net>
> To: "C320-List" <c320-list at catalina320.com>
> Sent: Friday, August 31, 2007 9:49 AM
> Subject: Re: [C320-list] Fuel filter bleeding
> 
> 
> > All excellent advice.  In steps 2 and 3 I find it very handy to use
> an oil
> 
> > filter wrench of some sort on the Racor cartridge.
> >
> > The Racor filter element should come with a new gasket.  I forget
> if it 
> > also includes a new O-ring for the bowl.  When you are removing the
> filter
> 
> > element from the Racor in step 2, pay careful attention to the
> orientation
> 
> > of the gasket on top.  It has a top and a bottom and is not
> symmetrical. 
> > If you reinstall the new one upside down then it will leak.  By
> looking at
> 
> > the old one when you remove it you can learn which is the top.  I
> need to 
> > write this down in my service notes, but somehow never have.
> >
> > At the beginning of step 9, do not start the engine while the bleed
> screws
> 
> > are still open.  They need to be closed first.
> >
> > I usually replace the Yanmar secondary filter on the engine at the
> same 
> > time as the Racor.  It's cheap and I'm bleeding the system anyway,
> so why 
> > not.  You have to pump more fuel during the bleeding process this
> way, but
> 
> > with the little pump on the Racor that's easy.  Plus the lifting
> and 
> > tapping in step 6 seems to be unnecessary when you do both at once.
> >
> >
> > Jeffrey Hare wrote:
> >> Hi Crosby,
> >>
> >> If the clear bowl does not have any water or sediment, then
> there's 
> >> simply
> >> no reason to bleed it from the bottom of the filter.  That's just
> how you
> >> drain excess water from the separator should it collect any.  And
> if you 
> >> are
> >> just draining the water/sediment from the bowl, you want to leave
> the 
> >> fuel
> >> tank stopcock open.  Then there will be no need to bleed anything
> after
> >> doing this, as you've not introduced any air into the system.
> >>
> >> When changing the Racor filter, that's a different story.  You
> should do
> >> this with a full fuel tank so that you have an easier time with
> the 
> >> bleeding
> >> process.
> >>
> >> 1) In this case, you would shut off the fuel tank stopcock.
> >>
> >> 2) Unscrew the Racor filter (leaving the plastic bowl in place at
> this
> >> point).  Many people use large ziplock bags slipped up around the
> filter 
> >> to
> >> keep any diesel from spilling into the bilge.
> >>
> >> 3) Unscrew the bowl from the bottom of the Racor, clean it and put
> it 
> >> back
> >> on the new filter, reinstall the new one not too tight.
> >>
> >> 4) Reopen the fuel stopcock.
> >>
> >> 5) Loosen the flat white plastic cap flush on the top of the
> filter and 
> >> this
> >> should allow fuel to free-flow and fill the filter and bowl.  When
> you 
> >> get
> >> clean fuel with no bubbles out of the top of the filter vent,
> tighten the
> >> cap up and move on to the next step.  (replacing the engine
> mounted 
> >> filter,
> >> or just bleeding the line)
> >>
> >> 6) On the top of the engine-mounted fuel filter, there should be a
> bleed
> >> screw. If done properly, this should be the only other place you
> need to
> >> bleed air from.  I suggest following the fuel hose from the Racor
> and
> >> lifting it and tapping on it to move any bubbles that may be in
> the line 
> >> to
> >> work their way up to the secondary filter on the engine.  7) Once
> you're 
> >> pretty sure any major bubbles have moved along, loosen the
> >> bleed screw on the top of the engine mounted filter, and slip a
> ziplock 
=== message truncated ===



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