how long can i run the engine safely without cooling water? engine is a Merc 3.0L.

On 5 Nov 2004 20:23:05 -0800, (IDT 512) vaguely
proposed a theory
.......and in reply I say!:

remove ns from my header address to reply via email

Let's know when you find out!

how long can i run the engine safely without cooling water? engine is a Merc 3.0L.

************************************************** ***
Have you noticed that people always run from what
they _need_ toward what they want?????

Old Nick wrote in message . ..

Let's know when you find out!


Actually i was wanting you to conduct the experiment for me

On Fri, 05 Nov 2004 20:23:05 -0800, IDT 512 wrote:

how long can i run the engine safely without cooling water? engine is a
Merc 3.0L.

There was a thread here recently about someone loosing an impeller vane or
something like that after running a motor very briefly out of the water.

But I know that the fishermen in certain places in Mexico beach their
boats at full speed, and lift the motor up out of the water while it is
still running as the bow hits the sand. Doesn't seem to hurt their
impellers.

This was probably not a really helpful post, but it's about all I know.
;-)

--Mac

There was a thread here recently about someone loosing an impeller vane or

something like that after running a motor very briefly out of the water.

That would likely have been my problem. This was with a small outboard (4hp)
and I ran the engine very briefly out of water and it trashed the water
impeller. I got the damaged one back and I can see why it was destroyed. The
impeller has rubber vanes which make direct contact with a hard plastic
housing. Use in water works just fine as the water acts a lubricant and
removes any heat real fast. But out of water, it would be like taking a peice
of rubber and rubbing it on a peice of hard plastic. It would heat up very
fast and leave rubber on the hard plastic in no time at all. Once a little
rubber gets put down on the hard plastic, the friction goes up, more heating,
more damage..

Dont know whats in your configuration but my advice would be to not run the
engine at all out of water. Its not about overheating of the engine, its all
about the water cooling pump getting destroyed and costing you a big hassle.

Assuming the outdrive is not connected (impeller would fail within a few
seconds) and assuming adequate lubrication and assuming raw-water cooling
and assuming the boat had been in the water and therefore the block was full
of water and assuming the belt to the water pump was disconnected ... the
water would soon boil off ... after that ... or assuming no cooling water
.... exhaust is water cooled so manifold/risers could warp, water hoses could
melt, head could warp, depending on the engine lubricant (some of that
synthetic stuff is pretty good) pistons may or may not seize ... .

Wild guess ... 3 minutes tops ... please post your findings :-)


"IDT 512" wrote in message
om...
how long can i run the engine safely without cooling water? engine is a
Merc 3.0L.

On 5 Nov 2004 20:23:05 -0800, (IDT 512) wrote:

how long can i run the engine safely without cooling water? engine is a Merc 3.0L.

The engine will hold up, the exhaust may eat up the rubber hose, and
the rubber impeller in the out drive may be consumed.
How much are you willing to sacrifice? If nothing, then use a muff and
water hose - always. It makes such a pretty rainbow if you select a
gear.

Brian W

engine will overheat within about 5 minutes. Bigger problem is you will
destroy the rubber impeller on the water pump.
"IDT 512" wrote in message
om...
how long can i run the engine safely without cooling water? engine is a
Merc 3.0L.

"Edward Quillian" wrote in message ...
engine will overheat within about 5 minutes. Bigger problem is you will
destroy the rubber impeller on the water pump.
"IDT 512" wrote in message
om...
how long can i run the engine safely without cooling water? engine is a
Merc 3.0L.

5 minutes??? i was thinking closer to like 15-20 seconds! I want to
start it up in the garage every once in a while and was wondering if i
can run without the flush kit to avoid getting the garage floor all
wet, otherwise id have to pull it out to the street each and every
time.

"IDT 512" wrote in message
om...
"Edward Quillian" wrote in message
...
engine will overheat within about 5 minutes. Bigger problem is you will
destroy the rubber impeller on the water pump.
"IDT 512" wrote in message
om...
how long can i run the engine safely without cooling water? engine is
a
Merc 3.0L.

5 minutes??? i was thinking closer to like 15-20 seconds! I want to
start it up in the garage every once in a while and was wondering if i
can run without the flush kit to avoid getting the garage floor all
wet, otherwise id have to pull it out to the street each and every
time.
Plus
- no need to drag the trailer out of the garage
Minus
- possible engine overheating
- possible water pump impellor damage
- engine fumes in the garage

And then I'd wonder about the plus and minus of starting it "now and then"
and not really being able to run it long / hard enough for it to warm up.

I'd be talking to your dealer, but if it's properly shut down, the battery
is kept charged, and the fuel you use to start it is fresh, I'd suspect that
it would be more reliable and last longer if it was left alone between
seasons. This from a person who lives where we can boat all year, and has a
diesel inboard.

Now that's sure to attract some criticism....
David