Originally Posted by Acushla
The pump should be fine for wear if it was replaced in 2009 although impeller replacement could well be required if you have overheating
The engine will need approx 12 litres a min at 1200 rpm
to provide adequate cooling.
Raw water cooled engines shouldn't run above 80 C as calciferous deposits will form in the waterways above this temp. The engine efficiency doesn't mind it running hotter but the salt water
deposits become a problem.
Thanks Acushla! 12 liters is roughly 12.6qts. I doubt we are quite that high. When measured with the output disconnected going to a bucket we measured roughly 8 qts/min (7.5L/min) at idle which is ~950 rpm. I will try the test again and try to get to 1200 rpm. We put everything back together last night and we are getting cooling water with the exhaust.
What has been done to date:
1 New impeller/seal and light sanding
of the plate to remove goo. (no change in symptoms)
2 removed exhaust elbow
and cleaned (not blocked but dirty) (no change)
3 replaced thermostat and found impeller piece of indeterminate origin probably PO as I change these annually to avoid this occurrence resulted in some water flow.
4 changed exhaust hoses (mixing elbow to muffler
to outlet) the first was going bad and the latter was REALLY bad. The rubber in each had bubbled creating at least three 50+% blockages. The latter one had rubber rot
. It's easy to ignore these hoses. Won't do that again. Helped water flow significantly.
5 this weekend check what passages in the engine I can get to to make sure no other impeller parts
Did I miss anything? At this point I'm mostly through so may as well complete the inspection