On Sun, 21 Dec 2008 22:50:10 -0500, hpeer wrote:


If you are going to install "taps" in the line for uses other then
engine cooling you MUST be sure that these taps are isolated with
valves and not used while the engine is running.

There are valves and I will heed this admonition.



The main strainer should/must be located below the water line so that
with the sea cock open the strainer fills.

The original installation of the strainer was most assuredly ABOVE the
water line. I believe that it is still slightly above but I am not
positive.

Well now, you've got me digging into Calder. While the text does not
specifically say to install the strainer below the water line the
diagrams, although fairly diagrammatic, surely tend to indicate that is
the way to do it.

While a rubber impeller pump is self priming I believe it is advisable
to make the system as much self priming as possible. Perhaps I should
have said it is better to have the strainer below the waterline...
The sooner you get water to the pump the less chance of overheating
the rubber impeller.

I do (at least at times) get water flow through the system with the
engine off. This MUST be due to a siphon effect. I can't swear that it
happens when I am having the overheating problem.

You should have a vented loop somewhere in the system to prevent
siphoning when the engine is off. I don't know how your engine is
plumbed but most systems have a vented loop between the engine and the
exhaust elbow. The top of the loop is above the waterline with a vent
to some distance above the loop. If you don't have this it is likely
that sooner or later you will fill the exhaust hose and then the
engine with salt water.... which is a headache that aspirin won't cure
:-)

Well I now have one MORE thing to put on my summer to do list.

Make sure strainer is below water level.

Ideally the system from thru-hull thru the pump will be under water
and self priming.

Cheers,

Bruce
(bruceinbangkokatgmaildotcom)