Water in an OMC 5.0L (GM) motor

[TB Boat]

We have a 1987 OMC 5.0 Liter engine and have steam surfacing through the crank case ventilator hoses coming off the valve covers. We have replaced the heads and associated gaskets thinking this would cure the problem, but it still exists. In a related or unrelated problem the engine will bog down and miss mightily when acceleration is attempted, particularly quick acceleration. Also, to further complicate matters, there does not seem to be water on the oil dipstick leading us to believe that the block is not cracked. Where else could water penetrate? And, what might cause the bogging and missing? Fuel mixing with water or an electrical malfunction? Any advice or ideas would be greatly appreciated.

 

[hondon]

Re: Water in an OMC 5.0L (GM) motor

Since you don't appear to be leaking into the oilpan ,an exhaust mani leak would be a likely suspect.Also the flapper valves at the top of your y pipes may be allowing water in if you launch on a steep ramp or are often in a heavy following sea.

 

[TB Boat]

Re: Water in an OMC 5.0L (GM) motor

Thanks for that insight. We will check the exhaust manifolds and those flapper valves. It would make sense that water, because it is on the top end of the engine, would be entering this way. I am not sure if this would cause it to run so poorly at higher RPM's though, could it be the primary reason?