So here's the postscript --
There was not really anything wrong with the Kohler genset. So all this drama and angst was for bugger-all.
I will recap the story in case it might help someone else.
My genset shut down due to high temperature a couple of months ago. It turned out that the seawater strainer was packed with seaweed. Cleaned it out, and the genset ran again. IF I HAD LEFT IT AT THAT, I WOULD HAVE SAVED A HEAP OF TROUBLE. Everything which happened after was self-inflicted.
I decided to check the impeller, and pulled off the sea water
pump cover. It looked ok, so I put it back together again and cranked it up. Oops! Forgot to open the seacock, so now the impeller is disintegrated. It took all kinds of agony to get the sea water side of the cooling
system working again. Meanwhile, I opened the fresh water side to find, to my horror, brown sludge. It seemed to me that the water was going down, and I thought I saw bubbles. So I was sure that I had a breach in the fresh water side - probably exhaust
But I finally got the sea water side completely cleaned out (took two rounds of surgery on the heat exchanger) and working right, and lo and behold, it's now working fine again. Fresh water is not going down.
The brown sludge must be from green and pink antifreeze
getting mixed somehow.
Just now I made the symbolic gesture of putting the sound enclosure back together -- a demonstration to myself that I'm not wrenching on it anymore.
During this time I had so little confidence that I would get it running again that I actually bought a Honda
. So now I have a backup.
Panic and overreaction! I htink I need to dig out my copy of Zen and the Art of Motorcyce Maintenance
and read it through again.