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

From: jd <jdood@...>
Date: Tue, 8 Sep 2009 09:13:42 -0700

On Sep 8, 2009, at 8:00 AM, Lee Shuster wrote:

> JD,
> One tool that you'll find invaluable is the illustrated OMC Parts
> Catalog. Available FREE online at BRP-OMC or CROWLEYMARINE.COM. OR
> you can but a REAL HARD COPY at BRP or look forever on eBay. I feel
> like a broken record, but I get the idea few of us have these, by
> the nature of a lot of the questions that crop up here.
> Careful study of this "EXPLODED" diagram will revel (4) bolts
> holding each cyl head to the block. It is a simple as your lawn
> mower, times 6 cylinders. With the OMC PARTS CATALOG it's like you
> have X_RAY vision!

Yep! HAve em all already and refer to them all the time. However I
couldn't quite decipher exactly how the head comes off from the
diagram I have (for a '68). From Bill's reply, sounds pretty easy.

> New Parts for the 3.7 Litre or 225 cu in ODD_FIRE BUICK V6 are
> relatively plentiful and easy to obtain including rebuilt short or
> long blocks. Even the OMC log-style. exhaust manifolds are still
> available, but they are expensive, see below)
> Nothing particularly expensive or specialized, as GM and Jeep built
> this engine for years. Just don't confuse it with it's 231 cu in
> (3.8L) even-fire sister. Anything you might need for this engine is
> available, if you carefully explain what you have and ask the right
> sources. This was probably the second most popular GM engine that
> OMC used after the 100-110-120-140 Chevy-II 4-banger.

The explaining what I have is gonna be the hard part. I can probably
get them through NAPA, have had good luck with them for other
gaskets. But telling them year of my engine is the challenge.
Boat is apparantly '64, but I had engine swapped last summer for an
apparent '70. I'm about 85% confident that's the year, but the
mechanic who told me that was wrong about some other stuff. I would
like to know for sure. How do I find out for sure?

> If this were my project, I'd start by having getting help to remove
> the stern leg. Then I'd carefully determine if there's room on your
> boat to pull the engine and intermediate out as a unit to gain
> better working access in a clean shop environment.

I have room/shop/hoist. A little nervous about doing it, but it's
a road I need to go down at some point ("pulling the engine") and
would love to know how to do. But pull the intermediate and engine
as one unit? I know if I pull off the heads and no obvious loose
part drops out, I'm gonna have to go deeper into the
engine.......which I'm guessing is't going to be possible w/o pulling
it right? Gulp.

> easy to stress (causing cracks) in the head mating flanges by
> lifting on the manifolds, so DON'T DO iT!). This will cost you big
> money. If it were mine, I'd carefully remove the exhaust manifolds,
> before removing the heads, to reduce the weight and possibility of
> ruining the manifolds.

Makes complete sense, although for some reason my manual specifically
says to leave them on when removing from engine and then take them off
on the bench.
> And Bill's right, treat that motor to a nice valve job. They'll most
> likely install modern hardened valve seats (for lead free gas).

I am all for this - makes sense while things are torn apart.......but
this is all first time territory for me. What exactly does this
entail? Where do I take them? I know my local NAPA had a sign about
some attached machine shop - will that work? How much should I
expect to pay? Will I notice it in the end?

> The timing is right to get started on good off-season project.
> Also, the fact that you mentioned a spark plug with NADA-gap is
> SIGNIFICANT. That plug most likely has encountered MECHANICAL
> interference and will PROBABLY be a clue as to where the SOURCE of
> your strange NOISE is.

I thought about that, then thought - "nah...couldn't be!" So by
mechanical interference are you suggesting something loose in the
cylinder a hitting the end of the spark plug and bending the gap
closed? It seems like a stretch, but then again, I have a
mysterious rattling noise and a what looks to be bent tip spark plug -
so maybe. Not really sure how anything could be in a cylinder - and
the engine still be able to run so well for all this time.

> BTW, what year/model is you boat? From you pictures, your Buick V6
> appears to have been retrofitted from a 72-73 era OMC. Do you have a
> serial number or model number off the engine tag?

> It's not all that important, just curious.

haha - see above. yeah, need that. Where's the tag? Here's what
I "kinda" know from last summer's verbal stuff the mechanic was
telling me: '70 engine, attached somehow to original '64 outdrive
stuff. But then there was also a lot of the "I don't know man, you
got all kinds of stuff in there" comments being made. Get the

I know there's a plate on the flywheel housing. But that is
apparently the original part. Where on the engine itself can i find
a stamp or plate that might tell me the year?

> Lee
> On Sep 8, 2009, at 7:56 AM, BLDFW wrote:
>> 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!
>> -Bill
>> 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" <omc-boats@...
>> >
>> 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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Received on Tuesday, 8 September 2009

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