Loss of Cooling Water?

[rjolm]

I am restoring a '75 Ericson 29. I now have the A4 running(at last).Water flow thru the exhaust is fine and then after maybe 10 or 15 min it stops? This has happened twice. This last time was the first time with the boat under power and all seemed to be running fine (about 4 knots @ 1/2 throtle). After about 20 minutes I did not see any water coming from the exhaust so I shut down the engine and sailed back in. What might cause the water/ no water situation. I am on a fresh water lake and this is a raw water cooled engine ignition is hot wired presently and I do not trust any of the gauges. The last time this happened in the slip I checked the (New) impeller, hose fittings and thru hull all appeared normal with water flowing as expected. ???

[Sony2000]

The cam opposite the impeller could have worn too thin, causing not enough pressure under a greater demand for water, and higher RPM.

[hanleyclifford]

It is possible you have an intermittent clog probably in the manifold water jacket. Try removing the water output fitting and see how clear is the passage.

[sastanley]

I agree with Hanley...some piece of trash (maybe an old piece of impeller or something similar) is lodged in the water jacket somewhere..it flops around for a while and eventually jams itself at an exit point like a hose barb & water flow stops. When you shut down the engine and stop pulling water into the pump, it dislodges and rests again until you restart and it gets lodged at the exit point again.

It will be tough to nail this one down!

[JimG]

I had a similar problem last week and went down to the boat prepared to find the worst, but it turned out to be some vegetation in the raw water thru-hull. Since I had the stuff, I did an acid flush anyway.