J wrote in
:

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





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

On Jun 9, 9:54*am, Le Moose 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,
*wr
ote:

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 pu
lled the
pump off the front of the engine and everything
appears to
be ok
there. We pulled off each individual cooling hose and
chec
ked for
blockage and there was nothing to be seen. Can someone
ple
ase give me
some suggestions as to where I can look next to fix
this o
ver heating
problem. I even ran water backwartds out of the
outdrive t
o check for
blockage and there appeared to be none.
THanks in advance
Justin

Check the thermostat. *It's easy to do at home. *Hang i
t in a pot with
some water on the stove and a cooking thermometer. *Add
h
eat. *Watch
the themometer and the thermostat. *You'll see it open
ar
ound 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
shoul
d it run
cool with the thermostat out?
Justin- Hide quoted text -

- Show quoted text -

The thermostat is required. *Most of the housings use
press
ure
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,
wha
t engine
manufacturer do you have? *Do you use the boat in salt
wate
r or
fresh? *Is the cooling system raw (no heat exchanger) or
cl
osed (has a
heat exchanger)?

I'd still check the manifolds and risers for clogging.
*The
y 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
drivew
ay?- Hide quoted text -

- Show quoted text -

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 b
uttom 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 w
ith 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 t
here 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 us
ed 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 w
ater. I
do not see a heat exchanger, the water gets pulled into
the bo
at
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
the
re needs
to be something in the thermostats place to force the
fresh wa
ter
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 -

- Show quoted text -

You are correct, that is a chevy small block. *In auto land
t
hey call
them 350's. *And I would agree that in fresh water the
exhaus
t system
should still be ok at that age. *Sounds like you have
checked everything. *When you ran it without a thermostat
did it stil
l 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 woul
d not
expect a blown head gasket but if its still overheating a
compr
ession
check wouldn't hurt but I would think you'd notice running
prob
lems.- Hide quoted text -

- Show quoted text -

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.
Aft
er I
had the head re-done I replaced the alternator/waterpump
belt an
d the
alternators pulley due to it was the wrong pulley and was
worn b
adly.
I tigehtned the belt and the waterpump was secure. *I don't
kn
ow abotu
the 350's but as stated before, my 3.0 runs at approx 135
degree
s
temperature.- Hide quoted text -

- Show quoted text -

I thought about that as well. *But in the v8/v6 engines the
bel
ts also
turn the power steering pump and the alternator. *Usually
there
are
two belts and both go around the wwater pump. *You usually
noti
ce
issues with the belts squealing when you turn or not charging
the battery before overheating issues. Plus he has had the
recirculat
ing
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
pret
ty
low range. *A few of the newer ones are starting to come with
1
60deg
ones. *These really should be replaced with 147s if the boat
is
used
in salt water. *Lower temps lessen the corrosive effects of
sal
t
water. *I prefer the 147 anyway. It's hot enough to prevent
idl
ing
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
somethin
g to
think about.- Hide quoted text -

- Show quoted text -

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 wh
en
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 -

- Show quoted text -

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 -

- Show quoted text -

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


On the Volvos a break in the hose from the outdrive would absolutely
casue the problem you describe because there is vacuum in the hose. In
other words, the raw water pump on the engine sucks up the water all the
way from the inlets at the bottom of the outdrive. If there was a break
in hose, it would suck air right in, especially at high RPMs. Also check
for obstructions at the inlets. Sometimes you can suck up some debris
that gets stuck in there. Also, one other easy thing: check your ignition
timing as well. BTW, the thing that slowed your engine is not so much a
defense, but your engine feeling ill. Don't let it happen if you can, or
sooner or later you'll end up with a warped head or worse.