"Ree-Yees" wrote in message . ..
Two minor prods with the 1987 Sea Ray. It has a 3.7 liter mercruiser I/O
engine with a closed coolant system. So I have a antifreeze tank, overflow
tank, and a big cylinder on the side that antifreeze and water runs through.

To keep the antifreeze in the overflow tank between the add and full
lines I usually have to add in one to three cups of coolant into it each
time I take the boat out. I can start the boat up and turn it on and off
and run it for a while in the yard and the coolant amount stays the same and
no smoke comes out the back.
When I take it out on the lake and I turn it off in the water and let it
sit there for any amount of time more than a minute or so, and then start
it up a bunch of whitish smoke comes out of the back appearing to come from
the exhaust. It smells like exhaust with a hint of antifreeze. This is
where I am losing the coolant, but I dont know where its leaking at. Oil is
not milky and this problem has stayed consistant for the whole summer so
far.

The second problem that may or may not be related to the first problem
is that I have a leak in hte boat. The leak is down at the bottom of where
the outboard peice comes through the transom. The leak is not big enough to
make the bilge pump run for for a little bit every once in a while, but
water is definitly coming in. To get to whatever is leaking the outboard
peice is going to have to come off. How much to places usually charge for
such a task?

Thanks for any info you got!
Cameron

Sounds like a cracked head. When the motor is cool or lighly loaded -
no leak. Once its loaded and heated the head contorts slightly and
the crack opens, letting small amounts of water into the cylinder.

You can try a coolant system pressure test, but if its cool it may not
happen. You can warm it up first - With the radiator cap OFF!! and
try a pressure test. I had the same problem on my old I/O, but it was
intermittent. Finally had the motor torn down and the mech showed me
the head cracked near a valve seat.

Thats the bad news. The good nes is that if you have to pull the
motor anyway you're going to have to pull the outdrive and you can fix
that other leak.

Good Luck

FishFan