[OMC-Boats] delving into scaryland....

From: jd <jdood@...>
Date: Mon, 7 Sep 2009 22:30:40 -0700

right on the heels of getting my switch issue overwith, and having a
fabulously smooth 30 min test at WOT right after the other day, I
was ready for a real outing. but of course, not without a new issue
to solve springing up. and not a pretty one. I was at the dock
(fortunately) and had just got back from my test run. Was playing
with idle trying to get it to go down to where it's supposed to
(sticky cable issue i think). in the spirit of trying to learn what
does what, i pulled off the spark arrester and started playing with
the flapper inside the carb. a tiny little brass screw that
partially held the flapper together was barely screwed in and sure
enough dropped down into the black abyss of the carb, never to be seen
again. I put stuff back together, started, no probs -smooth.
started moving the red throttle lever back and forth. all of the
sudden a clanking noise. however, coincidentally NOT the screw - a
much bigger clanking noise, and only at low idle - often causing
stalls. And in fact, i had heard this same noise 2-3 months ago
during a start up. immediately shut it down. it never came back,
and i forgot about it. so here it was again, this time a lot worse
and causing engine to stall. a car mechanic guy happened to be at
the dock, listened around the engine with me, sounded like it was
coming from the port side, deep within somewhere. It's definitely
the sound of a "metal piece" sort of bouncing and clanking around
inside the engine. It's not a rattle type sound, more of a random
clanking - like coins in a dryer. And it sounds big - not like a
tiny brass screw, but a nut or something bigger. ugh.

So long story short, he suggested i start with the valve covers and
see it anything is loose. the remove the intake manifold. as you
can see, have done both. jiggled a tiny little piece of solder
(from a previous owner's attempt at repairing carb flapper) out of the
IM, but no brass screw. So now I'm on to the only next place I can
go, the cylinders. Pulled the plugs out, nothing unusual with
them. One had NO gap whatsoever, but probably unrelated. time for
new plugs regardless.

So my questions are these: I'm about the pull off the cylinder
heads. have never gone this far into any engine. and am flying
somewhat blind. yes, i have all OMC 3 original manuals. yes, i've
read them. they aren't much help. So excuse my ignorance beyond
this point. But there's no way I am handing my boat off to another
mechanic for another year. Gotta go it alone.....

1)As shown in the photo. there appear to be about 8 bolts holding
the heads on. 4 inside, 4 down by plugs. but unscrewing those
doesn't look like it will do much because all the valve stuff. So
if i undo the 3 bolts holding that bar of levers, will it just come
off easily and allow for the rest of the head to come off somehow, or
will springs go flying everywhere? I don't wanna mess with valves if
i can help it. just wanna get to the cylinders. So much easier on a
lawn mower. Manual says remove heads WITH manifolds still
attached. But can't get to a couple bolts cause manifold gasket is
in the way. So i guess I'll be taking those off as part of this.

2) Will the head gaskets be trashed after this, or salvagable?
Anyone know right off hang if they are they out there for sale, or
one of those impossible to find way overpriced no longer made vintage
parts? Yes I will poke around online, but just trying to get an

3) After i get the heads off, I'm assuming I will be able to see the
tops of the pistons. I'm not expecting much, but perhaps I'll find
something obvious clanking around in one of the cylinders. perhaps a
coin, or a wedding ring, or maybe the top half of a spark plug.
probably not. So where is the next place deeper within that
something could be clanking around? what's under the cylinders?
Could the oil pump be making that noise? It wouldn't cause the
stalling though.

glad it's the end of the season.

thanks for any help, Jeff D

Received on Tuesday, 8 September 2009

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