Overheated then hydro locked

[boatwakes]

Manifolds and riser connection gaskets have a potential failure point which would allow water to fall into the exhaust manifold ports and then potentially into an open exhaust valve but I would bet thats not your problem. Have you noticed excessive water in the bilge recently? Have you checked the oil again? Milky? High? Low? My fear is the block weakened and produced a very slight crack during the freezing season and that crack was then augmented by the overheat allowing water from a cracked cooling passage to enter the crankcase. I honestly believe the water in the cylinder (reversion) was a completely separate issue when you stopped the boat from high speed.

[SATige]

Hi again Boatwakes... After changing the oil, I ran the boat last Saturday, during the day the oil seemed good. I plan to check and change the oil again tomorrow. There was one outing that resulted in excessive water in the bilge but I'm sure (now) that it was from water leaking out of the shaft of the water pump, I found this condition the day it overheated. There was additional "oil" when I changed it, probably an additional qt (like you suggested). An engineer at Zero Off (my neighbor) first suggested failed intake gasket(s). This (in my non-professional opinion) could explain the hydro lock and water in the oil. I'm considering changing out the intake gaskets tomorrow, looks like the gaskets from a 2500 HD truck would be a direct replacement(?). Thanks again!

[SATige]

Checked the oil again yesterday, which had one lake day on it, it's clean and at normal level. I then ran it on the hose and still looks good. I drained and replaced, and old oil looks fine. The oil I took out last week is still milky in its container, I thought that it would separate but it hasn't. I also notice that it was only about 5.5 qt which is pretty normal, initially I thought I removed more than that. Everything is checking out normal, I'm left with nothing else to do, but run it till I break it.

[SATige]

By the way, the milky oil I drained a week ago, was in the motor at the time of overheat.

[boatwakes]

Ok cool, very good to hear. It is possible for the intake gaskets to leak but not probable unless the top of that engine has been off before and someone screwed up really bad. I'm still sticking with water reversion from the exhaust for the hydro. Check your trans fluid too, there is a trans oil cooler just after the raw water pump that could pinhole over time and turn the atf to pepto bismol.