Hey David, I sent you some replies on the googlegroup email. I use vaseline on the impeller blades and the O-ring. Chuck
> On 06/06/2025 12:31 PM EDT David Knecht via CnC-List <cnc-list@cnc-list.com> > wrote: > > > Hi Bill- I am on my way to the boat to do what you suggested. I like the > idea of smearing grease around the cover which should help if there are air > leaks. There is a vented loop from the output of the heat exchanger to the > exhaust elbow. I have not checked that yet so will keep that in mind. Dave > > David Knecht > Emeritus Rear Commodore/Thames Yacht Club > Emeritus Professor/University of Connecticut > Basketball Capital of the World > > > > > > > On Jun 6, 2025, at 11:38 AM, Bill Coleman via CnC-List > > <cnc-list@cnc-list.com> wrote: > > > > > > > > On Fri, Jun 6, 2025 at 11:28 AM Bill Coleman <colt...@gmail.com > > mailto:colt...@gmail.com> wrote: > > > > > Sorry for this redundant comment Dave, but to go over the sealing of the > > > pump, I would remove the impeller, smear a bunch of either vaseline or > > > silicone grease on the back and circumference and blades, push it on > > > firmly, maybe put a straightedge across the face of it to make sure there > > > is no space between the straightedge and the vanes. If your pump has a > > > recessed gasket space or O ring so that the metal plate actually touches > > > the edges of the pump, then there shouldn't be any space between the > > > cover plate and the rubber vanes. If the gasket holds it away, then the > > > vanes should be proud of the housing by that amount so the cover plate > > > *just* contacts the vanes.. Then put more goop on the cover plate so you > > > can create suction. In a perfect world, you would not need to do that, > > > but . . > > > Then check the hose coming out of the pump to see if the water comes out > > > right after the pump. > > > Also, Do you have a vented loop in that line anywhere, that might be > > > something to check out. > > > > > > Bill Coleman > > > Erie > > > > > > On Fri, Jun 6, 2025 at 8:21 AM David Knecht via CnC-List > > > <cnc-list@cnc-list.com mailto:cnc-list@cnc-list.com> wrote: > > > > > > > As I always told my students, there are no bad questions or dumb > > > > questions or insulting questions. Just questions. So I appreciate > > > > everyone trying to help. It is why I love this community. Knowing you > > > > are all out there gives me confidence to tackle problems that don't > > > > have YouTube videos to walk me through. > > > > > > > > > > > > To sum from some earlier questions: > > > > 1. I verified that the pump shaft is turning. > > > > 2. I am pretty sure the impeller is turning because the pump housing > > > > got very hot very quickly from a brief test engine run with no water > > > > moving. > > > > 3. I can find no obstructions to flow from the seacock to the pump. > > > > > > > > You comment actually makes me wonder if I have been working under some > > > > bad assumptions in doing diagnostics. I had presumed that water would > > > > flow rapidly into the raw water pump due to water pressure and the pump > > > > would move it along. But as you pointed out, the pump is quite a bit > > > > higher than the entry point, so maybe the pressure is fairly neutral > > > > there. If I open the seacock, with the cover off the pump, should I > > > > see water flowing into the pump? Does the pump simply move water that > > > > is already there due to pressure flow, or does the pump actually draw > > > > the water into the seacock/strainer by sucking it in? If the latter, > > > > then many of my tests have been beside the point and nothing is > > > > blocking the flow of water into the boat. It is more that the pump is > > > > not drawing the water in, which gets back to the air leak issues > > > > mentioned. > > > > > > > > 1. If it is air leaks in the pump seal, I would propose to use a > > > > gasket sealant line Form A Gasket in addition to the o ring to seal the > > > > cover? Any reason that is a bad idea? > > > > > > > > 2. I asked earlier, but is there possibly a pump priming issue? I > > > > have never heard of someone having to do anything to prime there raw > > > > water pump. I did read an online engine thread where people had this > > > > problem with a particular engine, but simply revving the engine got the > > > > pump primed and pulling water. Dave > > > > > > > > David Knecht > > > > S/V Aries > > > > 1990 C&C 34+ > > > > New London, CT > > > > > > > > > > > > > Your contributions help pay the fees associated with this list and help to > > keep it active. Please help by making a small contribution using PayPal > > at: https://www.paypal.com/paypalme/stumurray All contributions are > > greatly appreciated. > > > Your contributions help pay the fees associated with this list and help to > keep it active. Please help by making a small contribution using PayPal at: > https://www.paypal.com/paypalme/stumurray All contributions are greatly > appreciated. >
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