Re: [omc-boats] BAD NEWS

From: lib1@...
Date: Sun, 11 Dec 2005 11:36:32 -0700

Hi Ryan,

I'd say that before you go much further you probably need to pull the 225
and determine the health of the short block, ie the crankshaft, bearings,
pistons and rings. Most likely they are getting pretty tired and you won't
know how much damage has been caused with water breaking down the oil that
you say "looks like mud." This is best done with the engine out of the boat
so you can pull the oil pan and inspect the crankshaft and bearings.

If it were mine, I would not go to the trouble of "swapping" or
re-installing the even-fire 231 into the boat; without first thouroughly
checking out it's running condition as well. While it's on the stand, you
could pull the pan and check out it's crankshaft and also also check out
it's compression.

BTW, it's getting hard to fine an engine rebuilder who will still do the 225
Buick/Jeep V6, but Jasper Engines completely redo long-blocks if you send
them the core. Not sure what they charge these days, but I'm guess the
charges will fall in the $2000 to $2500 range, which is quite a bit more
than a small block Chevy V8, simply because they don't get much call for the
Buick V6 anymore. But you do get a fresh engine, including heads, that has a

Just a thought: ->>> I don't know about your 69 Sportsman, but I suspect
you could get the small block Chevy V8 to fit in your engine bay, as I did
on my 66 Sportsman. See:

 If you consider the SBC V8 swap you'll need the exhaust manifolds from the
210, 215, 225, 235, or 245 hp OMC. You should also change out the sterndrive
upper gear ratio from a similar V8-powered OMC electric stringer sterndrive,
as the V8 would be revving too high with the stock V6 gearing. SBC Chevy
parts (even OMC-specific) are plentiful and cheap on eBay. The 210 hp (307
cid - 5.0L) was used in the 68-70 19-ft Evinrude and Johnson boats. It makes
the16-ft Sportsman run much smoother and it gets better mileage than the V6,
because most of the time it's not working as hard.

Just curious if you have checked the sterndrive yet? You can tell a lot be
draining the vital fluids and looking for water or metal.

Lee Shuster

----- Original Message -----
From: "Ryan" <kmoore12@...>
To: <omc-boats@...>
Sent: Saturday, December 10, 2005 1:13 PM
Subject: Re: [omc-boats] BAD NEWS

>I check compression on all 6 cylinders 3 times each. I found that I have
>one bad cylinder that is squirting water out of it when I crank it over and
>the compression is low. First test was 100 then 90, then 70. :( The other
>cylinders were 125, 125, 130, 130, 145 average. Oh! The oil looks like a
>light colored brown mud.
> Should I change head gasket and possibly the head or just swap motors with
> that 231 that come out of a 83,84 Buick Regal?
> I'm still shooting for spring!
> Ryan
> ----- Original Message -----
> From: "Ethan Brodsky" <brodskye@...>
> To: <omc-boats@...>
> Sent: Saturday, December 10, 2005 12:08 AM
> Subject: Re: [omc-boats] new member
>> On Fri, 9 Dec 2005, Ryan wrote:
>>> Ok..I got a compression gage. The guy who loaned it to me said I should
>>> check not only the compression but also the tolerance between
>>> cylinders??? I assume that means make sure one cylinder isn't way more
>>> or less the than others. Any idea what the tolerance is + or - ? Is
>>> this necessary?
>> I recently picked up the factory service manual for the 1970 155 HP OMC
>> V-6. It specifies the following procedure for compression testing:
>> (a) Remove all spark plugs
>> (b) Put throttle and choke in wide open position
>> (c) Remove wire from coil to distributor cap and ground securely to
>> engine
>> (d) Attach remote starter switch to starter assist solenoid
>> (e) Insert compression gauge in spark plug port. Crank engine through
>> at least 4 compression strokes to obtain the highest possible reading.
>> (f) Check compression of each chlinder. Repeat a second time and record
>> the highest reading for each cylinder
>> (g) The recorded compression pressures are to be considered normal if the
>> lowest cylinder pressure reading is more than 75% of the highest
>> (h) Example: 129,135,140,121,120,100 - 75% of 140 is 105. Thus, cylinder
>> 6
>> is less than 75% of number 3. This condition, accompanied by low
>> speed
>> missing, indicates an improperly seated valve or worn or broken piston
>> ring.
>> (i) If one or more cylinders reads low, inject about a tablespoon of
>> engine
>> oil on top of the piston in low reading cylinder through the spark
>> plug
>> port. Repeat compression check on these cylinders
>> (1) If compression improves considerably, rings are worn
>> (2) If compression does not improve, valves are sticking or seating
>> poorly
>> (3) If two adjacent cylinders indicate low compression and injecting
>> oil does not increase compression, the cause may be a head gasket
>> leak between the two cylinders. Engine coolant and/or oil in
>> cylinders could result from this defect.
>> Also, for Mark (the guy with the boat that won't go), the shift coil
>> resistance should be between 4.5 and 6.5 ohms, not the 2.xx ohms I
>> quoted earlier. The current draw is specified as 2.2 +- 0.2 A.
>> Ethan
>> -----
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Received on Sunday, 11 December 2005

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