omc 2.3 newbie BAD BAD BAD Mechanics help!! GAH!

[becon776]

Re: omc 2.3 newbie BAD BAD BAD Mechanics help!! GAH!

ok,
brought the boat in for repairs..... here is what happened...

They did replaced the hose, did two oil changes.... Said they did a pressure check and it passed with flying colors.... and said it kept wanting to blow the hose again. they said that there was the wrong impeller on there (the one that was on there was too big and too high of a flow). replaced the impeller. called, I dropped 400 more bucks and they said problem solved it is ready to rock and roll.
so I was getting ready to go clean but thought... hmmmm I am gonna go out and give it a good test run before I put people in the boat and then wind up stuck. Thank god. I went out and as far as I can tell... theres no more problem with the hose trying to blow. I ran for a good hour with the engin cover off keeping an eye on things. dropped it to WOT. and did some laps..... after like 45 min... check the oil... gravy again. ugh... wtf!
when it was first running, it ran better than it EVER has. Then sure enough after a while you could hear the burp happening at high rpm's. from the gravy dripping into the carb. It's funny they said they ran it in their very small test pond for twenty minutes and oil was fine... everything was fine. I think this prob happens once the engine get up to it's peak temp.
What's going on guys? they said passed pressure test, so no cracked block or head gasket. so what gives? They had originally said that the water was getting in there when the hose blew and it was shooting water all over the place. I know that's not the case. DAMN IT! I just want it too run.. I am running out of $$ :-/

 

[rodbolt]

Re: omc 2.3 newbie BAD BAD BAD Mechanics help!! GAH!

ok.
as there is only one impeller for the cobra drives that should be your first clue.
now lets look at possible water entry points.
manifold, Riser,riser joint, head gasket or a crack in a head or block casting.
now lets look at water pressure popping off a hose.
something is causing excessive pressure in the cooling system, most likly a crack in the head or a head gasket allowing combustion gas to enter and over pressurize the system, a clogged riser will do it but will also overheat the engine fairly rapidly.
this aint rocket science nor quantum physics. it does require thought about each engine subsystem and how it interacts with the other.
there is no good way to check a riser, the manifold can be pressure tested.
good digital pics of the spark plugs would help, water burning in the combustion chamber leaves tell tale marks to the trained eye.
if NO water is present in the combustion chamber guess what?
we just eliminated a manifold,head,riser and riser joint.
I know the may say they pressurized the cooling system, but did they run a cylinder leakage test?
cooling system,10 psi or so, leakage test in the cylinder, 100 PSI. which one is most likly to show a leak ?
dont keep chunking dollars at it, use a logical sequence of testing.