Don't forget on a closed (rad) system with antifreeze the boiling point is
substantially higher then raw water and no pressure. Also, most carb based
cars ran 165's, wasn't until injection and pollution controls that the
higher 185's etc came in. One trick to make more power from an injected
engine is to run a 165 thermo and reprogram the computer to except that as
'closed loop' meaning fully warmed up. But it raises pollution. A boat
could run as high as a 165, but to go to a 185 (with typical 10% variance)
pushes it way to close to that magic 212 . Also, in an engine with a 165,
areas around the heads can run up another 20d without the thermostat seeing
that, thus the safety range.
Mark, if the thermostat proves to be the culprit, don't run without it,
replace it, they are only 8 bucks for a Chev and help not just mileage but
lubrication and so on. Also pistons and other critical parts are sized to
work best at a certain temperature.. Don't skip looking at the engine pump
as I suggested a while back. If it is worn, the added restriction of a
thermostat will cause your problem, removing that restriction isn't a fix,
getting a pump that circulates the water correctly is. Look to the
automotive side for the pump, same part (don't do so for starters,
alternators etc, but pump is the same)..
Greg
"Bowgus" wrote in message
news
About the 140 F ... could it be because the manufacturer realizes that a
lotta boaters run their boats at WOT (= heat) ... whereas most :-) auto
drivers don't?
OT: had the boat out first time this year ... ran just fine ... an
excellent
day out. Too bad the weekend is not looking good ... we're looking forward
to trailering down to Ivy Lea for the up to Gananoque, across and down the
US side, around the castle, back to Ivy Lea loop ... and the islands just
off Gananoque ... very nice.
"Bowgus" wrote in message
...
It's not "overheat" or "underheat" ... it's "uneven heat" that (I was
told)
may cause a problem ... it's ... one part of the engine is hot and one
part
of the engine is cold(er) than it should be because of the lack of
temperature regulation provided by the thermostat. I myself will run my
engines with the thermostat installed ... you guys can do (obviously) as
you
like :-)
OT: My mercruiser thermostat is 140 F ... I myself find that unususual
compared to an auto thermostat. My understanding ... an auto engine is
most
efficient around 235 F (achievable because the sytem is pressurized). So
...
why the low temp for the marine (version) engine?
"tony thomas" wrote in message
newsz5qe.31276$x96.130@attbi_s72...
Only problem w/ running an engine w/out a thermostat is you may never
warm
the engine to proper temp and you may find the engine running rich all
the
time. This will cost you in fuel but won't hurt the engine (except
for
possibly carbon buildup over a long time).
Won't hurt in terms of overheat as the max coolant is flowing all the
time.
If the engine overheats and warps something in this condition it would
really overheat w/ a thermostat installed as a fully open thermostat
adds
a
certain amount of restriction just due to the metal parts being there.
--
Tony
my boats and cars at http://t.thomas.home.mchsi.com
-
"Bowgus" wrote in message
...
A suggestion ... don't run the engine very long without a thermostat
...
even better, don't run without a thermostat at all. One of the
thermostat's
function I've been told is to ensure a relatively consistent engine
temperature preventing parts warp etc.. Having said that, I had a
thermostat
fail closed on a Toyota. I removed it and drove home from ...
interestingly
enough Johnstown near where you're at ... to Ottawa without any
apparent
problems.
I am going to try it this weekend with no thermostat and see what
happens. Stay tuned ...