It over heats cause you fried the impeller in the lower unit when you ran it
dry.
NEVER EVER run the engine without muffs on the drive and a good flow of
water.
Muffs are $7 or so ....throw away the water barrel concoction.
Now you need to pull the drive and install a new water pump.
Buy the complete set, more than likely your housing is f'ed up too now.


There in NO possibility it's air locked.
Again, you can't run the engine at all without muffs and water AT ALL
EVER!!!


"Dean" wrote in message
...
1987 Merc 3.0 Alpha 1 - 140 HP.

Reinstalled the manifold with new gaskets, tightened everything up.

We started the motor and ran it dry for maybe a minute or two.

Finally figured out how to make a water barrel for the outdrive that would
actually work, filled it with water and re-started the engine.

We don't seem to be drawing any water out of the barrel. Engine temp rises
above normal, and we pulled the brass plug out of the bottom of the
manifold--no water coming out.

My questions:

1/ What's the possibility the cooling system is "air-locked"? ...and would
it be normal to have to prime it with water?

2/ How long could you normally run this setup "dry" (outdrive out of
water)
before you damaged something? ...and what would be the first thing to go
(impeller?).

Thanks
Dean