[C320-list] Overheating

Mon Aug 22 14:16:07 PDT 2011

Jack, This may be too unique and obscure to be of general value, but on
the off chance you or others may benefit, here's a recent experience of
mine.  I have suffered from overheating and running hot for years on my
2005 with a 3YM30.  I have replaced numerous impellers and opened and
checked the exchanger to no avail.  Next on my to do list is replacing
the thermostat and checking the exhaust elbow, neither of which have I
gotten around to just yet.  But my "Aha moment" came this spring when it
overheated shortly after launching.  I have often found seaweed clogs in
the hose between intake and strainer (sometimes I feel like my system is
some kind of seaweed magnet!).  After removing the intake hose and
confirming it was clear, and checking impeller which was fine, I pushed
my finger into the strainer at the intake, outflow points as far as I
could and felt nothing there.  Not satisfied, I next unbolted the black
strainer housing from the bulkhead and held it up to the light to look
into the intake side, and what did I find but a little almost round,
black piece of something wedged in there tightly.  It almost looked like
a little bit of pea-stone, or a small acorn, but my guess is that it was
one of those little nodules you see on some seaweed.  And it was just
oddly shaped enough that some water was likely passing around it but not
nearly enough. Since removing this obstruction, flow has improved
dramatically - obviously - but I guess the real point of the story is
that you have to check every inch of the system, and every nook and
cranny where debris could possibly hide or get stuck. 

I still run a little too hot, so that thermostat and heat exchanger are
definitely next.  Good luck.

Dave H.
Dottie B  #1049

Message: 1
Date: Sun, 21 Aug 2011 16:58:24 -0400
From: "Jack McDonough" <mcdonough5 at verizon.net>
To: <C320-List at Catalina320.com>
Subject: Re: [C320-list] Overheating
Message-ID: <0585B6597A58431A82DFD2636058007E at johnf12eb04ca6>
Content-Type: text/plain; format=flowed; charset=iso-8859-1;
	reply-type=original

Warren & Lew:

Yeh, I did check the heat exchanger, expecting to find that "aha"moment.

But -- nothing there. I opened both the front and back. Now, however,
the 
engine pumps raw water like a champ. I'm now in the "if it ain't broke
don't 
fix it" frame of mind.

jack
#947

----- Original Message ----- 
From: "Warren Updike" <wupdike at hotmail.com>
To: <C320-List at Catalina320.com>
Sent: Friday, August 19, 2011 4:34 PM
Subject: Re: [C320-list] Overheating

> So, you probably have a Yanmar. Ours is a Perkins. I'm not sure there
is a
> difference re. lost impeller vanes.  Here is my story.  Bought the
boat in
> '04. No problem for three years. Then, on a cruise, engine began to
> overheat, of course with a 20kt following wind. Turns out there were
at
> least 4 blades in the front of the heat exchanger. None of them were
from 
> my
> tenure. So, surely it is possible to have old blades in the heat
exchange
> and not cause a problem until you are in the most inconvenient
situation 
> for
> the problem to occur.
>
> Warren & Pattie Updike
> 1994 C320 #62 "Warr De Mar"
>
> -----Original Message-----
> From: Dennis Harris [mailto:dharris02 at suddenlink.net]
> Sent: Monday, August 15, 2011 2:04 PM
> To: C320-List at Catalina320.com
> Subject: Re: [C320-list] Overheating
>
> Just a thought...could it be that a broken water pump vane or other
debris
> is in the exit end of the heat exchanger?  It could be loose so it
moves
> around but big enough to stop water flow out the exit if it stops
across 
> the
>
> outlet opening.  On time, water turbulence moves it away from outlet 
> opening
>
> and you get normal pumping/water flow.  Next time, turbulence moves it
so
> that it blocks the outlet, in which case, you get no flow and steam.
>
> Dennis Harris C320 694.
>
> ----- Original Message ----- 
> From: "Jack McDonough" <mcdonough5 at verizon.net>
> To: <C320-List at Catalina320.com>
> Sent: Monday, August 15, 2011 11:50 AM
> Subject: Re: [C320-list] Overheating
>
>
>> Dave:
>>
>> Yes, you may be right. The trouble may well be downstream. I was
hoping I
>> could avoid pulling more stuff apart but I guess I'll have to bite
the
>> bullet. Thanks for the suggestions.
>>
>> jack
>>
>>
>>
>> ----- Original Message ----- 
>> From: "Utility Email" <kswanson123 at comcast.net>
>> To: <C320-List at Catalina320.com>
>> Sent: Monday, August 15, 2011 11:05 AM
>> Subject: Re: [C320-list] Overheating
>>
>>
>>> Could there be a partial blockage in the mixing elbow or a partial
>>> blockage upstream of the strainer?  It sounds like you have
thoroughly
>>> checked upstream of the pump, perhaps checking downstream might find
the
>>> culprit?  If it came on suddenly, that would point to some type of 
>>> marine
>
>>> life blockage was ingested, but of the strainer is clear, then it
would
>>> have to be upstream from that. I am guessing:
>>>
>>> 1. That the mixing elbow may have carbon/corrosion build up.
>>> 2.  Water pump is not functioning adequately at low speeds.  I'm 
>>> guessing
>
>>> that the water pump is not providing enough head to force water
through
>>> the system. Seems like there could e a easy way to test this buy
>>> connecting a long clear hose between the pump outlet and the engine.
>>>
>>> Dave Swanson
>>> S/V Emily Ann
>>> 2007 C320 MK II, No. 1107
>>> Mukilteo, WA
>>>
>>> On Aug 15, 2011, at 6:13 AM, hcreech at comcast.net wrote:
>>>
>>>> Jack,
>>>> Unless I am reading this wrong you are running your engine at too
low a
>>>> rate of speed. This should not have any bearing on the water pump
>>>> situation but still way too low. If you continue to run at that low
>>>> speed you will only create a carbon build-up which is not good. I
run
>>>> mine continuously while crusing a 2800 RPM and only lower speeds
while
>>>> docking. When I took the initial diesel class they stressed that
low
>>>> speeds are very detrimental to diesels. They went on to say you
should
>>>> cruise at 2800-2900 RPM and can run at 3100 RPM for up to an hour
>>>> without causing any problems. The main point was to "Not Baby" the
>>>> diesel. Could be another problem, but regardless, if I am reading
this
>>>> right, you need to crank it up.
>>>>
>>>> Herb Creech
>>>> Cloud Chaser 606
>>>>
>>>>
>>>>
>>>> ----- Original Message -----
>>>> From: "Jack McDonough" <mcdonough5 at verizon.net>
>>>> To: C320-List at Catalina320.com
>>>> Sent: Monday, August 15, 2011 8:47:20 AM
>>>> Subject: [C320-list] Overheating
>>>>
>>>> A puzzling, intermittent overheating problem developed a couple of 
>>>> weeks
>
>>>> ago with the 3GM30F Yanmar in my 2003 C-320.
>>>>
>>>> While traveling at low speed from an anchorage to a newly available
>>>> mooring one morning (maybe 10 - 15 minutes running time), the
engine
>>>> overheat alarm sounded. I managed to pick up the mooring, after
which I
>>>> pulled the raw water intake hose at the seacock and determined that
>>>> water was, in fact, coming into the system. I then checked to see
that
>>>> the strainer was clear and, finally, took apart the impeller
housing 
>>>> and
>
>>>> inspected the impeller -- which was newly installed in May and
which
>>>> looked fine. I started the engine again and still got only steam
out of
>>>> the exhaust. A couple of tries later, however, the system once
again
>>>> pumped out water like a champ.
>>>>
>>>> I made a three-hour passage to another harbor under power the next
day
>>>> and everything was fine -- but the same problem occurred the
following
>>>> day. Again it blew steam -- but the following morning I got a
healthy
>>>> flow of water and headed home.
>>>>
>>>> Since then, I have again pulled the hose off the intake seacock
but,
>>>> this time, I took my digital wire coat hanger and fed it down
through
>>>> the intake passage to make sure there was nothing flopping around
in
>>>> there. I disconnected the other end of the hose -- at the strainer
--
>>>> and detemined that there was nothing in the hose. Then I removed
the
>>>> hose between the strainer and the impeller and confirmed that it,
too,
>>>> was clear.
>>>>
>>>> I have a sense that I'm more likely to be able to pump water if I
>>>> briefly goose the RPMs up to 2000 or a little more. But I've
consulted
>>>> my diesel guy and he says that shouldn't make any difference. It
should
>>>> pump water regardless.
>>>>
>>>> That's my story. Any ideas?
>>>>
>>>> Jack
>>>> #947
>>
>>
>
>
> 