[C320-list] Water in Diesel

[Jeff Hare]

Hi Larry,

The shape of the tank and position of the fill and returns lines will
naturally cause all the water and sediment to make its way to the inboard
forward corner of the tank where the fuel pickup is located.  So, except for
a small amount, the water and debris will end up in your primary
filter/separator (which is good because your tank won't accumulate junk like
flat rectangular tanks will).  If the tank is not full and sloshes a lot the
water mix in with the fuel and take a day or so to settle out and slide down
and collect near the front corner where the pickup is.  Then you might see
quite a bit of water picked up in the separator after starting the engine.  

There are a couple things I would check, but I suspect that it's time to
replace the o-rings on your fuel filler cap.  It's worth buying 4 and doing
all the caps.  This will likely solve the problem, but also check the fuel
vent.  On some hulls, the fuel and water vents are on the transom.  Others,
have either the fuel or water vent on the port stern quarter.  Ours was like
that and twisted facing forward when we got the boat.  I was worried it
would scoop water so I pointed it aft and swapped it with the water tank
vent line which was on the back transom.  I also made sure that the hose had
an elbow up before it lead to the vent so that if water got scooped by the
vent it would drain back out.

I suspect you just need an o-ring since this is a new problem.  Yes, I would
change the primary filter and it sounds like it's doing the job just fine.
Consider whether it's possible that the fuel had water mixed in it when you
refueled and it settled out?

BTW,  We have a Yanmar in our hull #809. We run a 2 micron Primary filter in
our Racor fuel/water separator and a 2 micron in the engine mounted
secondary filter as well.  I have changed the engine mounted filter 3 times
since 2001 and the Racor primary every other year on average.  With this
filter selection, the filter on the engine stays clean and only catches
debris that might make its way to the engine during primary filter changes.

Also, with this strategy, should the primary get clogged while under way, I
can be assured that I only need to change the primary to get things running
again.  If I used a 5/10 or 15 micron filter in the Racor, and a finer
filter on the engine, I will always have to change both filters underway
anytime the primary gets clogged, or maybe even sooner. This year's filter
changes confirmed that the primary Racor was quite black and the small
engine mounted one looked brand new.  

Good luck.
-Jeff Hare
#809

-----Original Message-----
From: C320-list [mailto:c320-list-bounces at lists.catalina320.com] On Behalf
Of Larry Frank
Sent: Tuesday, July 7, 2015 11:16 PM
To: C320-List at Catalina320.com
Subject: [C320-list] Water in Diesel

I would like to find out what the collective wisdom and experience of this
group is regarding water in diesel.

A few weeks ago I discovered about 1/3  to 1/2 cup of water in the fuel
filter water separator bowl during a routine check.  Prior to this discovery
the engine had run fine.  After this discovery I instituted a procedure of
checking the separator before every time I started the engine. Until this
last weekend I didn¹t fine any more water than a drop or two.  During this
period I probably ran the engine for 10 hours in smooth to light chop
conditions.

I cannot determine exactly how water got in the fuel but suspect either the
fuel source or a filler cap not completely tightened combined with rain
water.  In 20 years of owning WindSwept I have never had this experience and
I replaced the tank about 2 years ago so I do not expect sources like
condensation to be the source.

This last weekend after motoring for an hour into a good chop (20 knots on
the nose in rather exposed water) the engine RPM dropped from 2300 to 2000
RPM and would not increase with increased throttle.  Luckily we were now in
a position to sail and raised sails and shut down the engine.  I checked the
separator bowl and drained about 1/4 cup of water.  We sailed across Corpus
Christi bay and restarted the engine when entering the breakwater and
protected water.  The engine seemed to run fine and no more water
accumulated in the fuel bowl.  When moored in our slip I ran the engine for
about 20 minutes at 2000 rpm in forward and increased the throttle to max
and the engine rpm was smooth at 3400 rpm so there didn¹t seem to be any
fuel restriction at this time.

Now that you have the background here are my questions.

1.  Has anyone had a similar experience and did enough water eventually make
its way out of the tank allowing the problem to go away?
2.  Do I need to try to siphon or pump the water from the bottom of the fuel
tank?
3.  If I were to allow the engine to run when the separator fills with water
will the engine just shut down or will damage occur?
4.  Does the filter element need changing after water exposure?

Thanks,

Larry
WindSwept
C320 #246