Mercruiser 7.4L water in all cylinder heads

I have a 1994 mercruiser 7.4 L engine. Left in water 2 weeks wouldn't start. Water in all cylinder heads not in oil. Starter replaced no history of deiseling. Boat ran for 2 weeks wouldnt start. Water in all cylinder heads again. Docked stern out some wave activity. Is problem most likely exhaust manifold, valves, or flapper valves. Problem after you come back to boat when not used for a vouple of weeks.

Re: Mercruiser 7.4L water in all cylinder heads

Is problem most likely exhaust manifold,

Click to expand...

Ayuh,.... I guess that would be a logical place to Start....

Re: Mercruiser 7.4L water in all cylinder heads

This sounds strange in that if it was the manifold(s) you should only have water only in cyls that have open exhaust valves.(including maybe the cyls that are connected via the exhaust cross-over in the intake manifold)

So even it IS a riser gasket, riser, or exhaust manifold. There shouldn't be water in every cyl on each side. (unless every exhaust valve is warped/burned/not sealing etc)

Also,

Does it have (3" or 4" etc) riser extensions installed.....you may need them....The installation manual indicates a procedure to measure the riser height and water line to determine the relationship. (see the "Adults Only" sticky above for manuals etc)


Regards,


Rick

Re: Mercruiser 7.4L water in all cylinder heads

Thanks will check this out