View Full Version : 43L OMC cooling

CJ Inglis
04-19-2004, 07:41 AM
" I have an 87 4.3L OMC with a cooling problem. Everything works as advertized in the driveway with muffs and a water hose. I can disconnect the water supply hose from the engine (the one that comes from the outdrive) and water flows freely. But when I put it in the water, I get an initial flow (about one or two seconds) then it seems to be pumping air. And that air seems to be exhaust air. I tried it with the exhaust accordian hose disconnected from the outdrive and it seemed to work. Its' as if the exhaust air is getting into the water ports in the outdrive. Is that possible?
Anyway, I have replaced the impeller and the liner/housing seems to be fine. Anyone have any suggestions on why or how air could be getting into the water channels in the outdrive? "