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

You might have destroyed the impeller by running the engine dry for 2
minutes. Thats a helluva long time for the impeller to go without being
lubricated by water. Will water muffs work for your engine? If so, get some-
simplifies maintenance starts.


"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

Any chance it has freshwater cooling and pulls the cooling water from
the through-hull? I have such a 1987 model and found out it also has an
impellor in the leg, so when I start it on land, I have to furnish water
to the through-hull AND put muffs on the leg or the impellor burns up
and warps the gasket and makes it leak oil.

Capt. Jeff

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

Not everyone has access to pressurized water, making the barrel a
necessary evil. You can indeed run the unit in barrel, but muffs are far
better. However your problem is you ran the pump dry. In the time it
take for the starter to tun the engine to fire, you've damaged the
impeller. Once the engine starts and hits running RPMs your've most
likely destroyed the impeller, upper pump housing, and most likely the
pump base plate as well. Don't try an skimp by replacing the impeller and
cleaning the housing and baseplate. Do as the man said and buy the
complete pump kit.

Lesson: if your outdrive intake is not submerged or gettign water flow
keep the key out of the ignition.

Bob Dimond


In article , "bomar"
wrote:

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.

10 sec of dry running and you took care of the impeller
"bomar" wrote in message
...
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

Well, I answered part of my own question...

Took the water pump apart. All six blades of the impeller had broken in
half. Luckily, I found them all. Two were down the bottom of the cavity,
between the inlet plates.

MAYBE that's why it wasn't drawing any water (duh).

Ah, well, I never said I was a marine mechanic, just a cheap boat owner. (A
boat owner who's cheap, as opposed to the owner of a cheap boat).