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

From: BLDFW <bldfw@...>
Date: Tue, 8 Sep 2009 06:56:34 -0700 (PDT)

I've pulled a couple of engines apart to do a rebuild.  The tube or bar is just holding the valve rocker arms in place.  It rests on top of the rods and the springs.  The springs hold the actual valves and are held in place by a snap ring that holds the little round 'cover' you see.  You are safe to remove the bar and the rocker arms.  They will either lift out with the bar or will just rest on the rods and valves and you can pluck them off one at a time.
The heads, once unbolted, will have to be gently prided up to free them from the block and yes, they will be trashed so you will need a new gasket set.  Since you have already gone this far, I would seriously recommend considering going the next logical step and sending the heads out for a valve job.  Would be a shame to waste breaking the engine down this far and not doing that but then again, if it's not necessary, no sense in doing it either.
Good luck and keep us posted!
Dallas, TX
1970 Evinrude Explorer - 155 Buick V6 - OMC Sterndrive

--- On Tue, 9/8/09, jd <jdood@...> wrote:

From: jd <jdood@...>
Subject: [OMC-Boats] delving into scaryland....
To: "Evinrude & Johnson Boats of the 1960's and 70's" <>
Date: Tuesday, September 8, 2009, 12:30 AM

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 idea....

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

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