On Jun 11, 4:55*am, Le Moose wrote:
On 6/11/2010 3:34 AM, J wrote:



On Jun 9, 12:51 pm, *wrote:
On Jun 9, 1:13 pm, *wrote:

On Jun 9, 7:24 am, *wrote:

On Jun 9, 9:54 am, Le *wrote:

On 6/9/2010 9:14 AM, jamesgangnc wrote:

On Jun 9, 8:43 am, * *wrote:
On Jun 9, 7:26 am, * *wrote:

On Jun 9, 1:54 am, * *wrote:

On Jun 7, 5:17 am, * *wrote:

On Jun 5, 12:52 pm, * *wrote:

On Jun 4, 12:15 pm, * *wrote:

On Jun 3, 3:33 pm, * *wrote:

I have a2000fourwinns230 hrizon, and i am having an issue with it
over heating. I hooked it up to a manual temp gauge and it is running
around 230. I have checked everything i can think to check. we pulled
the impeller off the fresh water pump that pulls the lake water into
the engine and this rubber gear is in perfect shape. We pulled the
pump off the front of the engine and everything appears to be ok
there. We pulled off each individual cooling hose and checked for
blockage and there was nothing to be seen. Can someone please give me
some suggestions as to where I can look next to fix this over heating
problem. I even ran water backwartds out of the outdrive to check for
blockage and there appeared to be none.
THanks in advance
Justin

Check the thermostat. *It's easy to do at home. *Hang it in a pot with
some water on the stove and a cooking thermometer. *Add heat. *Watch
the themometer and the thermostat. *You'll see it open around 147 or
160 depending on which on it is.

Another spot to check is the exhaust manifolds and risers. *Those
commonly scale up until they are clogged. *The risers are the worst.
You can usually tell by probing in the hose connections. *Or just try
to blow through them.

I took the thermostat out of the boat and it still overheats with no
thermostat in the engine. I was wondering if the thermostat is
required to divert the water to the correct places, or should it run
cool with the thermostat out?
Justin- Hide quoted text -

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The thermostat is required. *Most of the housings use pressure
differential to get the water to go through the engine or to skip the
engine and go straight to the manifolds. *Either check the thermostat
like I described or get a new one. *You didn't tell us, what engine
manufacturer do you have? *Do you use the boat in salt water or
fresh? *Is the cooling system raw (no heat exchanger) or closed (has a
heat exchanger)?

I'd still check the manifolds and risers for clogging. *They are the
most commen thing to clog up.

Do you have muffs so you can run it in the driveway? *Does plenty of
water come out with the exhaust when you run it in the driveway?- Hide quoted text -

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The engine is a volvo penta 5.7 GSI. I believe this is a chevy engine.
I can run the engine in the driveway and water comes out the buttom of
the prop area and some comes out with the exhaust. I explained this to
afourwinnsmechanic and he says it does that so the water has a way
to get out if the boat is backing up. IT can either come out with the
exhaust or from the buttom of the outdrive, the path of least
resistance. I believe the risers are the pieces that come off the top
of the manifolds, and in that case we did take those off and there was
minimal surface rust in the risers. Then we taped off the hole for the
exhaust and ran water through the engine with a hose and water flowed
freely out the exhaust, as if it were going up to the risers. so the
manifolds and risers seemed to flow freely. The boat is not used in
salt water, I purchased the boat 3 years ago and never used it in salt
water, and I dont believe the previous owner used it in salt water. I
do not see a heat exchanger, the water gets pulled into the boat
circulated insidfe the block then spit out. I will have to put a new
thermostat in and try it again becuase I was using it the last 2 times
without a thermostat, but my knowledge of engines tells me there needs
to be something in the thermostats place to force the fresh water
through the engine. So I will get a new thermostat in and try that.
Any other suggestions are greatly appreciated.
Thanks in advance
Justin- Hide quoted text -

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You are correct, that is a chevy small block. *In auto land they call
them 350's. *And I would agree that in fresh water the exhaust system
should still be ok at that age. *Sounds like you have checked
everything. *When you ran it without a thermostat did it still run
hot? *I'd suggest you replace it with a 147 deg one. *That might be
what it had or it may have had a 160. *It's shaping up to be a real
puzzler. *I hope the thermostat solves the problem. *I would not
expect a blown head gasket but if its still overheating a compression
check wouldn't hurt but I would think you'd notice running problems.- Hide quoted text -

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Another thing to add. Is the alternator belt tight enough so the
engine water pump can spin efficiently? *That was one problem that I
had found out with my 3.0 when I suspected that the engine had a bad
head gasket (which it did) The alternator belt was about as thin as *a
shoe string and I could easily turn the engine pump by hand. After I
had the head re-done I replaced the alternator/waterpump belt and the
alternators pulley due to it was the wrong pulley and was worn badly.
I tigehtned the belt and the waterpump was secure. *I don't know abotu
the 350's but as stated before, my 3.0 runs at approx 135 degrees
temperature.- Hide quoted text -

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I thought about that as well. *But in the v8/v6 engines the belts also
turn the power steering pump and the alternator. *Usually there are
two belts and both go around the wwater pump. *You usually notice
issues with the belts squealing when you turn or not charging the
battery before overheating issues. Plus he has had the recirculating
pump off so he's had to loosen the belts and then retighten them to do
that.

I agree, most raw water cooling systems use thermostats in a pretty
low range. *A few of the newer ones are starting to come with 160deg
ones. *These really should be replaced with 147s if the boat is used
in salt water. *Lower temps lessen the corrosive effects of salt
water. *I prefer the 147 anyway. It's hot enough to prevent idling
problems,

I'm curious about the raw water pump. If it is engine mounted it
requires good suction on the input. There's a paper gasket on the
impeller cover that needs to be in really good shape. Also there is a
possibility the pump shaft seal could be leaking air. Just something to
think about.- Hide quoted text -

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I believe they are engine mounted on all the volvoes. *While I have a
merc I don't think much of that pump being in the bottom half of the
outdrive. *Just a PITA. *That could expalin it not overheating when
run on the trailer and supplied by pressurized water. *A piece of
clear hose from lowes could be used temporarily to watch for air
coming out of the raw water pump.- Hide quoted text -

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OK, so your saying I should use the clear hose to run from the fresh
pump up to the thermostat housing?
justin- Hide quoted text -

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Yea, you could pick up a piece of clear tubing the same size and
temporarily put that on it between the raw water pump and the
thermostat housing. It's probably 1" or so hose. Might have to be a
little longer if the original hose is molded. *When it's running it
should be all water or water with very minimal air. *If there is a
bunch of air it in then your raw water pump is sucking air somewhere.
That would test Moose's theory.

The position of the thermostat may also be important, there may be a
right way and a wrong way to put it in. *If you don't have a service
manual you can find ipb's on the net usually.

ok, so i put a new thermostat on the boat today, and also put a clear
piece of hose between the raw water pump and the thermostat housing.
Took it out on the lake and there was some air in the hose while we
were driving it, the boat only overheats when driven about 3k rpms. As
I was coming back to dock, I also noticed there was water shooting out
of the top of the outdrive, from the gap between the outdrive and the
back of the boat. I did a compression test and each cylinder had
between 90 and 100 psi and one was around 80. I pulled the dipstick
out and there was no sign of water in the oil. Was wondering if there
was a chance there was a possible break in a hose for the system that
brings the fresh water from the outdrive to the engine, that would be
letting air into the system or not supplying enough water to the
engine. There are two temp sensors that go into the engine, the one
that goes into the intake manifold, i took out and replaced with a
manual gauge that i have setting on my back seat, and the boat was
running around 230 when i was above 3k rpm, and twice the engine lost
power, to the point where i had to stop and let it idle for a second,
the temp would drop and i was able to drive it again. I was wondering
if there is some kind of defence system that prevents the engine from
running when it;s too hot.
Thanks again for any advice
Justin

Compression is around 150 on a new engine. Yours is pretty low but even.
You need to rerun that test later.
If you are operating at 230F you are on the threshold of doing serious
damage to your engine.
* Water shooting out of the top of the outdrive could be from a leak in
the exhaust bellow caused by age or being burned by hot exhaust.
I assume that the raw water pump is at the front of the engine vs being
inside the outdrive.
You need to perform the air bubble test on the inlet (suction) side of
the water pump to see if your air is being introduced before the pump.
Check that your hose clamps are tight.
With regard to the pump itself, You should install a new impeller and
gasket at the minimum. It is possible that the metal or fiber insert is
slipping inside the impeller at high speed.
You might want to start thinking about taking the boat to a Volvo shop.- Hide quoted text -

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I'm not really so familiar with the volvoes but I agree about taking a
look at the exhaust bellows between the transom plate and the
outdrive. Gettng overheated may have damaged it. Also if you saw a
lot of air in the clear line that does suggest you have a problem
somewhere in the supply to the pump. Again I don't know exactly how
the volves do it but if the pickup is in the outdrive then there has
to be a number of places it could be messed up. I'd guess by turnign
the drive hard to one side or anoher you should be able to find a hose
form the outdrive to the transom plate. Check that. If the exhaust
has burned theorugh the bellows maybe it has damaged that hose as
well. There will also be a hose from the transom plate up to the raw
water pump. Any place with damage or a loose connection will show you
the problem. Might be worth trying to pressurize it a bit using the
muffs with the engine off in the driveway. Use the hose water
pressure and then examine everywhere to see if water is leaking out
somewhere between the muffs and the raw water pump.