Good suggestion from Rich. Even a new impeller can spin.
Also, there may be a suction leak on the intake side of the pump. Disconnect
the discharge at the pump. Start the engine and check for flow there. (It
won't hurt the engine to run a couple minutes with no water flow.) Try to stop
the flow by blocking the hose with a rag or your hand. If the flow and
pressure are good, move downstream. If no flow or you can stop the flow then
the issue is the pump or ahead of the pump.
If the flow is good, disconnect the hose to the little elbow you cleaned.
Check for flow and pressure there.
Dennis C.
Touche' 35-1 #83
Mandeville, LA
>________________________________
> From: Knowles Rich <r...@sailpower.ca>
>To: "cnc-list@cnc-list.com" <cnc-list@cnc-list.com>
>Sent: Thursday, May 23, 2013 8:35 PM
>Subject: Re: Stus-List Overheating 3GMD - the plot thickens
>
>
>
>Suggest checking the raw water pump impellor to make sure the bronze insert is
>not spinning inside the rubber impellor. This can happen with a new or old
>unit and can fool you in an inspection as the rubber vanes may look perfect.
>
>
>Rich Knowles
>Indigo. LF38
>Halifax
>
>On 2013-05-23, at 22:00, "Don Jonsson" <dbjons...@shaw.ca> wrote:
>
>
>Hi
>
>I had previously sent out a message about an overheating diesel. The
>culprit, so I thought, was the knuckle going into the mixing elbow, because
>generally when I cleaned it, it worked again. For a while.
>
>So I finally took of the mixing elbow and gave everything a proper cleaning.
>I checked the water pump. I checked all hoses by blowing through them and the
>engine.
>
>I put it all back together and it all worked and water pumped like it is
>supposed to, except the water pump leaked a bit – needed a new gasket, but I
>knew that and just wanted to see if it would work. Got a new gasket and put
>it on. Started up and no water.
>
>I took out the thermostat and checked to see it worked – slightly corroded but
>it worked, i.e. opened in hot water. Put everything back together and started
>it up and a bit of water but too much steam. Took the thermostat out and put
>it in more carefully. Tried again, water running, no steam everything is
>perfect. Ran it for a while just to be sure.
>
>Turned it off. Waited a while (an hour) and started it up again. No water.
>
>So the problem is not the mixing elbow (and likely never was as it wasn’t that
>bad). Not the pump as it looks fine. Not the thermostat – I don’t think
>although I will replace it.
>
>The problem is sometimes the engine pumps water and sometimes not. And I’m
>stumped.
>
>This is a raw water cooled engine which makes things different. Has anyone
>had a similar problem and ideas for a solution.
>
>Also, it seems hard to get part numbers for a 3GMD and the local mechanic had
>to go find an old book. Is there any place online to find part numbers for
>that engine?
>
>Thanks to anyone that can help.
>Don
>
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