OK, changed the oil today, pumped out 9 liters ! of sludge, some of it so
thick that I couldn't believe my eyes. As indicated I have not had the boat
in the water yet (no time plus a big "?" with regard to the engine). Oil
filter contained almost no oil but water. I ran the engine last year on the
hose for about 20 min altogether. That was after putting new oil in the
engine (first change after getting it to run).
Considering short time that I had it running on the hose it seems like I
have a major leak. Since compression is quite high (140-160) I wonder
whether it is something else other then head gasket (cracked block?). Water
seems to accumulate in crackcase although as I said looks like also in cyl.
# 4. I ran the engine today for about 30 sec. (dry, no water). Seems to be
working, This a regular 305 8cyl. 5L OMC engine, nothing special about it.
I guess there is no way to avoid heads removal. I bought Block Seal (K&W
product) after I read some really good comments about it (many swar by it).
I planned to connect 2 exhaust water hoses (that are normally hooked to
manifolds) together and connect them with water inlet hose (unhook from the
outdrive - bell housing) thereby creating a loop. I planned to fill it with
water mixed with Block Seal and run it for 5 min. That should help seal
small cracks (wonder how small or big mine is). If no improvement I would
remove heads. In theory my plan looks OK but God knows.... Considering what
I've accomplished so far without taking the engine apart I'm still
optimistic although prospects are quite tough. What do you think should I
do? What is the most likely fault/damage here?





"Rod McInnis" wrote in message
...

"Proxy" wrote in message
.rogers.com...
1. The oil is not clear but rather milky. The oil level is much higher
then
it should be - about 2 inches on a dipstick higher then "full". This is
the
first oil after reviving the engine (see below) so I'm not sure whether
to
attribute milkiness to water leftovers or blown gasket. the oil level
though
is something new.

The milky color is due to water in the oil. If the oil level is rising on
its own that is a clear indication that you are still getting water into
the
oil.


4. there is rust in the intake below carb, there is also a rust streak
from
s. plug no.4 downwards indicating the water could have been leaking from
this plug socket

I would not expect water to leak out of a plug socket. If you have any
appreciable amount of water in the cylinder it would hydrolock.

5. I bought this boat with a seized engine, I soaked it, unseized, ran
it
several times (never on water), starts and runs OK.

Okay, that changes my previous recommendations!


When I unseized it I
cranked out lot of water from the cylinders (min. 1 liter).

How long had the engine been sitting with water in it?

What baffles me is that except for compression test (unexpectedly high)

I thought that the compression was rather high also. Could this be a
"high
performance" engine, which could have a high compression ratio (and thus
require 91 octane gas)???

If you tested the compression right after you got it to turn over for the
first time then there is a possibility that you still had some water in
the
cylinders. This would certainly raise the compression numbers. If you
haven't tested it since you actually had it running you might want to do
it
again.

I have all indications of blown head gasket.

A head gasket can fail in several ways. The gasket must seal the cylinder
pressure. There are also water passages that are under moderate pressure
(a
few PSI on a boat engine, up to 14 PSI on a closed cooling system). There
are also oil passages that are not under pressure.

A common failure is to have the pressure from the cylinder rupture the
gasket. The rupture can go to the outside, an oil passage, or the water
jacket. Such a rupture should show up on a compression test. Other than
that, a rupture to the outside might not be noticable. A rupture to the
water jacket would cause overheating on a closed cooling system but might
be
unnoticable on a boat with raw water cooling unless water entered the
cylinder when the engine cooled. A rupture to an oil passage would result
in excessive amount of "blow by".

It is also possible for the water jacket to seal to fail, either to the
outside or to an oil passage. To the outside would result in a visible
leak,
while a ruptuer to the oil passage would cause your crankcase to fill with
water. Since the cylinder is still sealed this failure will not show up
on
a compression test. Usually, this sort of failure is the result of a
warped
head, perhaps the result of overheating. If the head is warped, just
replacing the gasket may not fix the problem.

I would recommend removing the heads and examining them. This, of course,
requires removal of both the intake and exhaust manifolds, which it sounds
like you may have already done once. Generally, once you have the
manifolds
off getting the heads off isn't too difficult. This will also allow you
to
examine the cylinders to see if there is any rust issues inside.

Rod

Just did that. See my comments above. I tend to agree with Rod McInnis that
it looks like a massive oil passage-cooling system leak accompanied by much
smaller to the cylinder. That way you can have high compression and lots of
water in your crankcase like in my case. I see that as a "hotspot" in the
gasket that also could have potentially caused a crack/warp (I hope not). I
think that water jacket pressure test would reveal if I have to do both
heads or just one. It all boils down to good diagnostics and methodology.
Good troubleshooting is my forté although I have little experience with
engines. I'm quite technicaly inclined so dismantling the engine is not
something I'm scared of. The issue is to do just what is required, nothing
more nothing less. In my case: 1 or both heads? Would hate to find out that
the one I took off was just perfect. From compression test looks like odd
side looks good and the only anomaly is #4 on even side. Or am I missing
something?


"Ron White" wrote in message
...
I would change oil and filter, first thing. This will allow you to see if
water really is getting in the oil. Next, nothing you said but the clouded
oil and too high level would really point to a blown head gasket or
cracked
block. I would save that thought on the back burner and start with new oil
and go to the river and motor around a bit staying close to the landing
and
keep an eye on the temp. gage. Afterward , I would check the new oil for
water (cloudy?) and pull the plugs and see if old #4 looks weird. If there
is water entering that cylinder it should make that plug cleaner. Also
spin
it over like you did before, without plugs, and see if you get any water.
A
little river running under a load should make a suspected leak more
noticable. I hope your charmed motor stays that way.

--
Ron White
Boat building web address is
www.concentric.net/~knotreel

OK, guys here is the scoop. I took the head off on the even side that was
suspected of water leak. Head gasket in perfect condition, same with intake
manifold, both sides. Cylinders inside OK no issue, no rust, scuffs or
anything suspect. There are rust residues on the top of the cylinder (inside
the head) and valves are quite rusty. No. 4 has most rust although as I said
cylinder walls are OK, no rust.
Seemes like compression test did not lie and the undertaking so far has
rendered zero results. It was simply unnecessary. There has to be another
point of water entry. I'm not even thinking about takeing the other head off
as compression was perfect on all cylinders.
I've redone raisers last year (new gaskets, throughly cleaned, refinished
contact surfaces) but maybe I'd have to do it again. Still looking for
ideas.... Any input appreciated.



"Mikkilla" wrote in message
...

1.) have you checked the oil. if you have a blown head gasket you will end
up
with water in the oil see if its milky in color on the dip stick.
2.) Your impeller might not be up to par to keep the engine cool. What was
the
engine temp?
3.) was the water coming out at a study flow from the exhaust or was it
all
steam and not water or very little?
4.) the water "spray" you got if a very good chance it came from the water
that
got in to a uncovered Carb. Careful there you might have something rusted
up in
the intake area.

After thorough analysys I came to the following conclusions:
The leak may occur in these areas:
-water pump seal (this is Cobra and I have no detailed info about it, I need
to study it in depth, but it seems least likely)
-head gasket leak (checked and eliminated)
-cracked block (inspected it and haven't noticed anything unusual, still
need to do it again in depth, for now I see it as unlikely cause)
-leaking intake seal (even though I checked it and did not notice anything
suspect it seems to be the most likely reason considering the amount of
water)
-raiser leak (strangely the engine never stalled which would indicate
raiser/manifold issue, the other reason it is less likely is that there is
so much water getting into the crankcase that I wonder how would it be
possible for the cylinder with a healthy head gasket to pass water into the
crankcase - if not through the valves (unlikely) then how? the only answer
would be a cracked block).

Don't know if this is correct but I'm down to either cracked block ot intake
gasket. Considering, the engine ran fine and there are no indications of any
cracks... it looks like the intake dripping straight into the valley and
from there directly into the crankcase, looks quite logical. So what do you
guys think?



"Proxy" wrote in message
e.rogers.com...
OK, guys here is the scoop. I took the head off on the even side that was
suspected of water leak. Head gasket in perfect condition, same with
intake
manifold, both sides. Cylinders inside OK no issue, no rust, scuffs or
anything suspect. There are rust residues on the top of the cylinder
(inside
the head) and valves are quite rusty. No. 4 has most rust although as I
said
cylinder walls are OK, no rust.
Seemes like compression test did not lie and the undertaking so far has
rendered zero results. It was simply unnecessary. There has to be another
point of water entry. I'm not even thinking about takeing the other head
off
as compression was perfect on all cylinders.
I've redone raisers last year (new gaskets, throughly cleaned, refinished
contact surfaces) but maybe I'd have to do it again. Still looking for
ideas.... Any input appreciated.



"Mikkilla" wrote in message
...

1.) have you checked the oil. if you have a blown head gasket you will
end
up
with water in the oil see if its milky in color on the dip stick.
2.) Your impeller might not be up to par to keep the engine cool. What
was
the
engine temp?
3.) was the water coming out at a study flow from the exhaust or was it
all
steam and not water or very little?
4.) the water "spray" you got if a very good chance it came from the
water
that
got in to a uncovered Carb. Careful there you might have something
rusted
up in
the intake area.

After a long break I'm back with an update. I replaced the head gasket and
(surprise!) put it back together. After some tinkering I created a loop by
unhooking intake and water outlet hoses, attached new ones that lead to the
bucket with water. Filled the engine with water (mixed with block seal and
ran the engine for about 15 min. First impression: after 5 min. I checked
the oil and looked quite clear. I observed a water level in the bucket and
it stayed the same. No bubbling. In short it seems that head gasket
replacement together with intake seals did the trick. I pressure washed the
cylinder head and that has revealed some slight rusting around water ports
leading to the cylinder bore especially around cyl. no. 4, although not
only. Looks like a head gasket was leaking between the block and the head
gasket (underneath) although gasket itself was in perfect shape (not tight
enough?). That will probably conclude the saga. I'll check it soon where it
belongs: in the lake.
Thanks everyone for help and words of encouragement.



"Lawrence James" wrote in message
hlink.net...
Check for cracks on the sides of the lifter valley of the block. That is
a
common point for cracks when the engine is not winterized and freezes.

You can pressure check the system by clamping something inside the hoses.

"Proxy" wrote in message
.rogers.com...
1. The oil is not clear but rather milky. The oil level is much higher
then
it should be - about 2 inches on a dipstick higher then "full". This is
the
first oil after reviving the engine (see below) so I'm not sure whether
to
attribute milkiness to water leftovers or blown gasket. the oil level
though
is something new.
2. checked the impeller and looks fine, not damaged , no burn marks or
anything unusual
3. the water was coming out quite steadily also steam was present
4. there is rust in the intake below carb, there is also a rust streak
from
s. plug no.4 downwards indicating the water could have been leaking from
this plug socket
5. I bought this boat with a seized engine, I soaked it, unseized, ran
it
several times (never on water), starts and runs OK. When I unseized it I
cranked out lot of water from the cylinders (min. 1 liter). What I did
was
a
great success, no mechanic has ever given me any hope. It has stunned
everyone. I also unseized another boat of mine (20 ft.) using the same
method. Engine runs but the compression is at 60/70 on 2 cyl. so I know
I
need to hone and replace rings on it, to say the least. I took both as a
challenge, bought them and had them running within a month. The idea was
to
keep both in different locations so I could enjoy some diversity while
vacationing.

What baffles me is that except for compression test (unexpectedly high)
I
have all indications of blown head gasket. I have removed risers and
manifolds, cleaned them to perfection, installed new gaskets. If it was
a
riser gasket water concentration would be rather equally spread over the
side rather then 1 cylinder

Since this is a boat engine I cannot pressurize cooling system easily. I
thought of pressurizing the suspected cylinder but couldn't find any
inexpensive tool or method of doing it.