[C38] over heating

[PAUL NOTTE]

I have fresh water dissapering when I make power changes . At first I thought I had a plugged seacock however that was not the problem. At 2800 rpr every thing seems fine with little water loss , as soon as I power down the engin starts to overheat , seawater pumping ok although with the cover off the pump there is backflow leakage with the seacock turned off. There appears to be no leakage from anywhere . When I add water with the engine off it slowly leaks away .
Suggestions ? Before I start tearing things apart .
Thanx. 
Paul impulse