Re: water getting in my engine 2.5 litre mercruiser120 hp
Locate the hose between the thermostat housing and the exhaust manifold. Disconnect from the manifold and plug the hose air tight.
Then locate the hose between the transom shield and the thermostat housing. Disconnect hose from transom shield and plug the hose air tight. Adapt an air pump with a gauge to 1/8" npt pipe thread and screw into block drain and pressurize the block. It should hold 15 psi if the block is good. If it doesn't hold pressure, follow the sound of leaking air.