Re the difference - it's significant.
This is a heat transfer / cooling issue, not one where you can apply the
ideal gas laws and use Rankine or absolute temperatures.
If the engine block is at say 250F, the rate of cooling for 37 F coolant vs
85 F is (250 - 37) / ( 250 - 85).
More importantly, if temperature difference required to remove the developed
heat is say 100F, it will run at 185F in the Caribbean and 137 in the colder
water ...
You can't just restrict the flow or the temperature becomes uneven. So you
need a circulating system - might as well consider a fresh water one ..
David
"derbyrm" wrote in message
news:xBuKf.788735$_o.605338@attbi_s71...
Just to amplify the following advice a bit, engines run most efficiently
when HOT! The only reason your auto engine doesn't run a lot hotter is
that it's too hard to keep the pressure reasonable when you go much above
212 F.
The other potential problem is "shock cooling." Idle a bit and then turn
the engine off. Heat will percolate out from the exhaust and from the
combustion chambers. When it's started again, the cold water will cause
different parts of the engine to shrink at different rates and you can get
piston scuffing at least and possibly other dire actions.
That said, there isn't that much difference between the Caribbean's 85
degree water and your 37 degrees. The effects are calculated on the
"absolute" temperature scale, so it's 545 to 497 (10%) on the Rankine
scale.
Roger
http://home.insightbb.com/~derbyrm
"theMooseisLoose" wrote in message
news:8kuKf.34509$6f2.19385@trnddc02...
wrote in message
ups.com...
I am buying a used boat from Stony Point, NY. It has a Mercruiser V8
5.0 with 190 HP with 300 hours on it.
I live in Greenland. An island in the arctic region east of Canada
where the seawater temperature is around 36-37 F degrees. And thatīs
where there might be a problem. I am told that the motor is "use" to be
cooled of with warmer water temps around the more southern part of the
world. And when I get the boat and the motor is cooled down with
seawater that is 36-37 F degrees then it migth not run smooth anymore
or develop somekinda problem. Is this story a myth or is there
something to it? And if the story is right how can i prevent any
problem with the motor. I cannot install fresh water cooling system as
it is too late for this motor because it has already 300 hours of
seawater cooling I am told.
Any help or suggestions will be much appreciated.
Sal****er cooling is 'uncontrolled' water circulation drawn from under
the
boat- with very little control of the engine operating temperature. If
you
are concerned about 'stabilizing' the engine temperature, the only way to
do
it is by freshwater cooling. This will allow the engine to run at
operating
temperature (controlled by the thermostat) and at least run more
efficient.
And it is NOT too late to do this.