I have a OMC Cobra 5.0 in a 1992 Marada that started overheating the last time I had the boat out. The manifolds are cool but the block is very hot (Gauge goes quickly to 220). It appears that the thermostat isn't opening. I have installed the impeller kit in the lower unit, a new thermostat and a circulating pump. I checked the temperature gauge and that is fine. Yesterday I put a clear hose in the supply line from the lower unit to the engine and it appears I have air coming in along with the water. The higher the RPM's the more air I see.. What can cause this type of problem? Could this be my problem? Any idea's would be appreciated.
