Mercruiser 3.0 exhuast manifold

I have a mercruiser 3.0. I/O - I noticed water coming out from high up on the exaust manifold and running down the side of the engine block. I can't see where exactly the water is originating from but it appears to be coming from where the manifold meets the engine. There is a good amount of water coming out. I am wondering if it could be from the gasket. If it was cracked would it show a lot of water or little water? If it is the gasket how hard is it to replace? Thanks for helping.

 

You are in NJ. Was the engine properly winterized?

 

Thanks for replying Gonzo.

I drained the water from the manifold but did not add antifreeze. I tested it with muffs before putting it in the water and saw no signs of leak.

 

The gasket at the block doesn't have any water passages. If it leaks there must be a crack either in the manifold or the head. Are you sure it is not the gasket between the manifold and riser?