overheating mercruiser
 

i own a 1988 winners boat and it has 5.7 ltr 350 small block chevrolet with
an alpha one stern drive and it overheats . the engine is new and the
outdrive has been gone through by a cert. Mercruiser tch. i have replaced
waterpump, impeller,gauge,some hoses and have went as far as to take out the
engine and outdrive to reinspect all the hard work we have done just to have
an good runnin boat 2 enjoy Lake Erie with . i'm about at the point and takin
revenge out on my wonderful craft because i'm lost for answer so PLEASE HELP .
... stranded and overheatin in the middle of Lake Erie and need either a tow
or a ___________ ..... lets put are heads together and try to solve my
dilema!!!!!!!!!!

overheating mercruiser
 

On Wed, 16 May 2007 03:51:24 GMT, "ricksbasseyetus" u34236@uwe
wrote:

i own a 1988 winners boat and it has 5.7 ltr 350 small block chevrolet with
an alpha one stern drive and it overheats . the engine is new and the
outdrive has been gone through by a cert. Mercruiser tch. i have replaced
waterpump, impeller,gauge,some hoses and have went as far as to take out the
engine and outdrive to reinspect all the hard work we have done just to have
an good runnin boat 2 enjoy Lake Erie with . i'm about at the point and takin
revenge out on my wonderful craft because i'm lost for answer so PLEASE HELP .
.. stranded and overheatin in the middle of Lake Erie and need either a tow
or a ___________ ..... lets put are heads together and try to solve my
dilema!!!!!!!!!!

On the hard, with plenty of water to the earmuffs, does the engine
also overheat?

Brian W

overheating mercruiser
 

* ricksbasseyetus wrote, On 5/15/2007 11:51 PM:
i own a 1988 winners boat and it has 5.7 ltr 350 small block chevrolet with
an alpha one stern drive and it overheats . the engine is new and the
outdrive has been gone through by a cert. Mercruiser tch. i have replaced
waterpump, impeller,gauge,some hoses and have went as far as to take out the
engine and outdrive to reinspect all the hard work we have done just to have
an good runnin boat 2 enjoy Lake Erie with . i'm about at the point and takin
revenge out on my wonderful craft because i'm lost for answer so PLEASE HELP .
.. stranded and overheatin in the middle of Lake Erie and need either a tow
or a ___________ ..... lets put are heads together and try to solve my
dilema!!!!!!!!!!


My experience is with smaller sailboat diesels, so it may not apply
here. However, I've seen two causes of overheating that can go
undiagnosed. One is a air lock in the line, in particular a water
heater line which leads up from the engine, thus making it hard to
completely fill the lines.

The other situation is a problem in the heat exchanger. If it is
partially clogged, it will work fine at lower loads, but overheat when
the load goes beyond its ability to remove heat. Unless you can
measure the heat content of the waste water, there is not way to
determine this is the problem without looking inside.

In my case, I had a bit of eel grass that clogged several of the
internal HE pipes. Once figured out, it was easy to deal with. I was
reading yesterday about a case where Yanmar 75 hp engines had heat
exchangers that had been tested in manufacturing with a bad solution
that left a coating on the inside that reduced efficiency. The
problem had plagued the owner for several years until discovered a few
weeks ago.

overheating mercruiser
 

Ahhhh... thermostat stuck?

overheating mercruiser
 

thanks Brian for your reply and your answer is that the engine does not
overheat with the earmuff on Only when you have the boat in drive and under
a load and i've looked at about everything!!!! WHAT YOU THINK ?????
Brian Whatcott wrote:
i own a 1988 winners boat and it has 5.7 ltr 350 small block chevrolet with
an alpha one stern drive and it overheats . the engine is new and the
[quoted text clipped - 6 lines]
or a ___________ ..... lets put are heads together and try to solve my
dilema!!!!!!!!!!

On the hard, with plenty of water to the earmuffs, does the engine
also overheat?

Brian W

--
Message posted via BoatKB.com
http://www.boatkb.com/Uwe/Forums.aspx/cruising/200705/1

overheating mercruiser
 

NO MIKE , THE THEROSTAT IS NOT STUCK OPEN . I'VE ALREADY THOUGHT ABOUT THAT ..
... NEW WATERPUMP, NEW HOSES , NEW IMPELLOR, I'VE CHECK OUT THE ENGINE TIMING
AND EVEN CHECK HAD THE NEW HEADS CHECK OUT BECAUSE I THOUGHT THERE WAS THE
PROBLEM BUT, NOT....... NEXT QUESTION PLEASE!!!!!

wrote:
Ahhhh... thermostat stuck?

--
Message posted via BoatKB.com
http://www.boatkb.com/Uwe/Forums.aspx/cruising/200705/1

overheating mercruiser
 

"ricksbasseyetus via BoatKB.com" u34236@uwe wrote in
news:724ad9421fa33@uwe:

NO MIKE , THE THEROSTAT IS NOT STUCK OPEN . I'VE ALREADY THOUGHT ABOUT
THAT .. .. NEW WATERPUMP, NEW HOSES , NEW IMPELLOR, I'VE CHECK OUT THE
ENGINE TIMING AND EVEN CHECK HAD THE NEW HEADS CHECK OUT BECAUSE I
THOUGHT THERE WAS THE PROBLEM BUT, NOT....... NEXT QUESTION
PLEASE!!!!!


If the timing's fine....I want a compression check on all cylinders, not
just the ones you can get to. I wanna know of the head gasket's leaking
or the head is cracked, both of which will make the compression suck.
(Or, maybe a cracked ring, but let's be more positive than that for
now...(c;)

Because of the new heads, I'm thinking they may be warped, even a tiny
bit is enough to make the head gasket leak and go bye bye...causing it to
overheat because it's running LEAN...never a good thing.

What color is the exhaust pipe inside? Dark Chocolate brown, I hope.
Talk to me about what ALL, not just a couple of those plugs look like
after you pull them out for the compression check. Any of them look
white? or very light brown? (lean) Are they all the same color? What
color?

So many questions....I'm going to bed. Let us know these answers.

We milled the heads flat on a GM350 that was overheating and running
lean. Temperature dropped and the thermostat closed! Acceleration, with
ALL the cylinders pulling like mad, not just half of them, was most
impressive....(c;

Pray it doesn't need a ring job or has leaky valves. Does any cylinder
"wheeze" when its cranking before it fires? Start easy cold?

Larry
--
Grade School Physics Factoid:
A building cannot freefall into its own footprint without
skilled demolition.

overheating mercruiser
 

* ricksbasseyetus via BoatKB.com wrote, On 5/16/2007 11:17 PM:
thanks Brian for your reply and your answer is that the engine does not
overheat with the earmuff on Only when you have the boat in drive and under
a load and i've looked at about everything!!!! WHAT YOU THINK ?????

So have you looked into the heat exchanger?

overheating mercruiser
 

Combustion chamber leak into the water jacket could be pushing away
cooling water. Or something not right with the exhaust manifold
waterfall plumbing. Have you looked at the condition of the plugs -
specially looking for squeaky clean ones?

Brian W

On Thu, 17 May 2007 03:17:57 GMT, "ricksbasseyetus via BoatKB.com"
u34236@uwe wrote:

thanks Brian for your reply and your answer is that the engine does not
overheat with the earmuff on Only when you have the boat in drive and under
a load and i've looked at about everything!!!! WHAT YOU THINK ?????
Brian Whatcott wrote:
i own a 1988 winners boat and it has 5.7 ltr 350 small block chevrolet with
an alpha one stern drive and it overheats . the engine is new and the
[quoted text clipped - 6 lines]
or a ___________ ..... lets put are heads together and try to solve my
dilema!!!!!!!!!!

On the hard, with plenty of water to the earmuffs, does the engine
also overheat?

Brian W

overheating mercruiser
 

What does the compression read in each cylinder?

Brian W

On Thu, 17 May 2007 03:27:59 GMT, "ricksbasseyetus via BoatKB.com"
u34236@uwe wrote:

NO MIKE , THE THEROSTAT IS NOT STUCK OPEN . I'VE ALREADY THOUGHT ABOUT THAT ..
.. NEW WATERPUMP, NEW HOSES , NEW IMPELLOR, I'VE CHECK OUT THE ENGINE TIMING
AND EVEN CHECK HAD THE NEW HEADS CHECK OUT BECAUSE I THOUGHT THERE WAS THE
PROBLEM BUT, NOT....... NEXT QUESTION PLEASE!!!!!

wrote:
Ahhhh... thermostat stuck?