[C320-list] Overheating

[Jack McDonough]

Dennis:

Excellent idea. Someone else made a similar suggestion. I'll add that to the 
list of things to check. Thank you.

jack
#947



----- Original Message ----- 
From: "Dennis Harris" <dharris02 at suddenlink.net>
To: <C320-List at Catalina320.com>
Sent: Monday, August 15, 2011 2:03 PM
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
>>
>>
>