You did replace the impeller, right? Bill Coleman
On Thu, Jul 24, 2025 at 10:18 AM David Knecht via CnC-List < cnc-list@cnc-list.com> wrote: > Yes- this started with limited water from the exhaust and overheating. I > realize I have two separate water circulation paths. I have had the heat > exchanger cleaned and pressure tested, checked the muffler and intake > path. Last reasonable possibility is the water pump. I know that the > existing pump is pumping water when there is no resistance and that worries > me. My concern is what happens if I install a new water pump (in progress) > and it doesn't fix the problem. I have made too many errors in diagnosing > the problem so far to be confident in where the problem lies and I am also > worry about multiple simultaneous system failures. So if the thermostat > failed or the fresh water pump failed, I would get overheating. That would > not explain sense of limited water from the exhaust, but that might not be > the real problem and difficult to measure. I am just trying to think about > every aspect of the system. Dave > > David Knecht > S/V Aries > 1990 C&C 34+ > New London, CT > > [image: pastedGraphic.tiff] > > On Jul 24, 2025, at 8:31 AM, Rick Brass via CnC-List < > cnc-list@cnc-list.com> wrote: > > David; > > IIRC correctly this string started with an overheating problem? > > The water coming out of the exhaust is raw water. That side of the cooling > system general has only the through hull, the water strainer, the heat > exchanger, and the exhaust elbow; all connected by various hoses. > > I believe you have addressed everything except the heat exchanger. Have > you cleaned out the tubes in the heat exchanger? If you sail in salt water > they get deposits over time. For my 36hp Westerbeke that is a routine > maintenance item every two or three years. For my engine the cleaning tool > is a bronze brush intended for the barrel of a .22 rifle that I bought at a > sporting goods store. > > The fresh water side of your engine (which actually cools the engine) has > the thermostat, if it has one, the heat exchanger takes the place of the > radiator in your car. The fresh water side of the system is just like your > car engine. My engine has a coolant recovery tank - which makes monitoring > the level of the coolant easy. Not all engines have one. > > If you have addressed everything in the raw water side of the problem and > it still overheats, it may be time to look at the freshwater side of the > engine. > > Rick Brass > Imzadi. 38mkll > La Belle Aurora 25 mkll > Washington, NC > > > Sent from my iPad > > On Jul 23, 2025, at 7:02 PM, Jonathan Tebbens via CnC-List < > cnc-list@cnc-list.com> wrote: > > > https://www.westerbeke.com/parts%20manual/200144_m4-30_parts_man.pdf > Pg 31-32? > > Jon Tebbens > > '78 Mega 30 > Katherine > > On Wed, Jul 23, 2025 at 5:13 PM David Knecht via CnC-List < > cnc-list@cnc-list.com> wrote: > >> I am in the process of installing a new water pump to see if it fixes my >> engine overheat problem. I still think the main problem is not enough >> water coming out of the exhaust so keying on the water pump. But something >> occurred to me today while working on it that I had not thought of before. >> Is there a thermostat somewhere in the engine (Universal M4-30)? Can those >> malfunction? I presume if it did not open, the engine would overheat? I >> don't even know where the thermostat is so have never looked at it but I am >> concerned whether that is something I need to check. Dave >> >> David Knecht >> S/V Aries >> 1990 C&C 34+ >> New London, CT >> >> <pastedGraphic.tiff> >> >> 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. > > 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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