Hello,
I can do some things with an engine, but this may be out of my hands. I have not ran my boat in a couple years and it was put away correctly for winter storage.

this season I did start it up and ran it out of the water with muffs on and everything seemed to run just fine. Ran it for 5min and shut it off.

I walked around the boat and left it sit for an hour. when I came back there was milky water on out. Pretty clean water too. The dip stick was thin oily water looking pretty tan in color

Any Ideas where to start ?
It's a 305 chevy small block with a 2 barrel carb
Merc inboard/ outboard
Thanks

You say that it was put away correctly, but that can mean different things to different people. Do you know for a fact that the block was drained and filled with RV antifreeze? Not sure of your experience level or that of the person who winterized it, but you have to be careful to make sure you jamb a screwdriver up into the water drains, or else it may not drain all the way due to sediment building up. Also, some boats have an external oil cooler that can crack and allow water to mix with oil. Likewise, a cracked exhaust manifold or riser can allow water to leak back into the exhaust and ultimately into the engine.

Barring this, check the condition of the manifold / riser joint. This can once again leak water into the engine when it runs. Is this a salt water boat? If so, you may have a corrosion issue in the manifold or even the block / heads allowing water to get into the oil.

Sometimes milky looking oil can be a simple issue of water condensation, especially when running on a hose, because the oil cannot heat up enough to burn off the water vapor. However, if the dipstick looks like a milkshake, then it sounds like you have bigger issues. Good luck - bummer of a way to start the season.