Yup, I appreciate the question. I just don’t know how to answer it. So I set out on a long trip last summer, where I really needed the engine
. And it crapped out. Over heated, after running cold for a couple of days. Some things you just can’t figure out.
So the manifold comes off and, not knowing what else to do, I just start poking at it with pointy things. I think I cut like 6 inches of Small wire rope
and chucked it up in a drill and used that to get Into various places. Dental picks, etc. Just keep poking around trying to figure out where the water goes. There are internal passages that are not obvious.
After a while I kinda got to where I could feel the difference between the base metal and the crud. Lots and lots of patience, and beer
I then poured water in so I could see where it ran out. And I then taped over various ports
so the manifold would hold water. Then i put in Ospho and let it sit. For a few hours. Go to the club house, have a cuppa, swap lies. Rinse out the manifold, run water through. Dig out what ever is now loose. Tape it up, pour in some OSPHO go to the club house, etc. The trick was to wait until it would quit off gassing. Then you have the crud out.
THen I reassembled and put some Ospho in a bucket and ran a hose from the thermostat housing back to the bucket. Then open the decompression lever and pump
some Ospho through. At first it would off gassing pretty good, the line from the thermostat into the bucket would bubble. We think I did this about 3 times until it quit bubbling.
That seems to cure the problem, after that she was making good water. I did a test of about a half hour, ran her hard up to temp. I could see the thermostat cutting in and out. Then I had to pull her to do some work
on the hull
Anyway, that’s what I did. Lots of patience picking around, and beer.