[C320-list] Raw water pump question

[Joe Luciano]

Sounds to me like your thru hull valve may leak by....

Joe Luciano 
Second Wind
#1024
Anacortes, WA

Sent from my iPhone

> On Jun 29, 2019, at 4:29 PM, Greg Flanagan <greg.flanagan at shaw.ca> wrote:
> 
> When I have changed my impeller I have always experienced this as well. I couldn’t analyze why. However, I just use two bowls, one to fill and one to empty, below the impeller housing until I am finished and closed back up. I will be interested to know the logic of it but as I am not “open” for long it hasn’t bothered me. Yes too, when I close the seacock to clean the raw water strainer, this is no continuous water flow!!
> 
> Cheers,
> 
> Greg 
> Hoop Dancer #1076
> Sidney, BC 
> 
>> On Jun 29, 2019, at 10:05 AM, Crosby Roper <VMDatSEA at hotmail.com> wrote:
>> 
>> I went to change the impeller on the raw water pump last weekend on my 2004 C-320 (hull 1054). As always, I closed the sea water intake under the aft berth. When I removed the cover of the raw water pump, there was a steady flow of water coming from the lower opening to the pump. I thought it would stop at some point but it continued in a quite healthy fashion throughout the process of changing the impeller. This has never happened before. I removed the raw water filter by the sea cock to see if perhaps there was a problem with the seacock itself, but there was no flow of water from the through hull at that site, so I am baffled as to what is causing this. I looked in the yanmar 3YM30 manual and it mentions the possibility of siphoning but I'm not clear exactly where it would siphon from. I checked the anti-siphon loop in aft port lazarette and the duck bill valve appears to be fine. Has anyone else experienced this? Any input is appreciated.
>> 
>> Crosby  Roper VMD
>> s/v Tethys
>> San Diego, CA