On Jul 23, 11:28*am, JR North wrote:
As you will recall, In our last episode, I was preparing to install the
new starter in my Merc. 5.0. I did a compression test with the old
starter in place, 150 all around. After sitting 2 weeks, the new starter
is in; I cranked it with the plugs out (no manifolds installed yet) And
it spun 3 revolutions with a *Clack* every 360°. I thought in this brief
time that possibly a tooth was sheared on the flywheel ring, but after 3
revolutions the engine locked and would not turn. ****. I was thinking
maybe a socket I had holding the Qjet choke open had somehow fallen into
the intake manifold and wedged an intake valve open. Ok. I put a chain
wrench on the balancer and found I could rotate the engine backwards,
but would lock at the same point forwards. I pulled the valve covers,
expecting to find an offending intake valve hung open, with slop in the
rocker arm as a result. Found it, alright, but an exhaust valve, not
intake. Feeling up the #4 exhaust port with my finger, I can feel the
broken end of the exhaust valve stem. The valve head is loose in the
combustion chamber, preventing the piston from reaching TDC. DOUBLE
****. In the 2 weeks since the compression test, the #4 exhaust valve
seized in the guide, and on cranking, because the valve is at an angle
with the piston, was broken off. Now I get to pull the heads......
Oh well, the engine is 18 years old, has 495 Hrs on it, and with all
that down time, a seized valve is not unusual.
JR

JR Said:
*So, after I got home from July 4th cruising, I flushed the engine on
the muffs. Shut it off and went to restart about 30 min later.
Hydrolock. Pulled the plugs, and sure enough-clear water out of several
cyls. The starter sounds like a garbage truck now also. ****.
I should consider myself lucky-this is only the second set of manifolds
in 18 years, 95% salt water, due to careful and thorough flushing.
I found the best deal on manifold/riser kit he (free shipping)

http://stores.ebay.com/Doug-Russell-Marine

and cheap price on NEW Marine starter for Mercruiser 5.0 he

http://stores.ebay.com/Rareelectrical

and, lowest cost on exhaust boots (I'm doing the whole thing here...)

http://www.go2marine.com/

No affiliations...

I pulled the manifolds last night, and squirted about 30cc ATF into the
cylinders and cranked it through. Because I applied anti-seize compound
to the manifold and riser bolts on the last job (1996) all the bolts
came right out. In fact, after loosening, they could be screwed out by
fingers. I don't have any such hope for the starter bolts-they're
original and I'm dreading pulling the starter tonight.

JR

JR Said:
What a BITCH. I had to custom *make a special tool to get the starter
bolts loose-will post pics soon so youse manly guys that get your
hands dirty can benifit from it. Absolutely no way I could get them to
budge with just a wrench. I'm really amazed they came out at all.
Prolly a good thing I'm doing it now; Cruis;n Rulz! is 18 years old
and unlikely I could get the starter out down the road at all. It
would really suck to have to pull the motor to replace a starter...
Anyway, waiting for all my good deals to arrive, and to get back on
the water.
JR
HOME PAGE:http://www.seanet.com/~jasonrnorth

That's disappointing. You put some oil in it when you took the
manifolds off so I'd have hoped for better. Next question is what did
that piece of valve do to the cylinder and piston top. Going to pull
both heads or just the problem one? Your compression sounds good.
I'd be tempted to just replace the valve and go but 500 hours is a bit
of time....... Makes me glad I boat on a lake, no salt water.