OMC -what's bad - motor or drive?

packman35

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I am considering a used boat with an OMC Cobra 3.0. I understand the hesitation with OMC since they are no longer made. But... are they good engines/drives and is it just getting them serviced that sucks? Or were they a POS? What are the things to look for when looking at a used boat with one?

Lots of questions. Thanks in advance.
 

mthieme

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Re: OMC -what's bad - motor or drive?

I'm in the minority (of 1) on this one and I'm sure I get a flame or two, but...
My set up is 20 years old with thousands of hours. I've never had the motor (4.3) apart and she still runs great with no apparent signs of (internal) old age. She is fresh water cooled which makes a huge difference - I'm in brackish water. The motors themselves are mostly all Chevy engines (Mercruiser or OMC). You will find some stray Fords and even Chrylsers. All the trimmings are one marine brand or another and that's where you start talking Mercruiser or OMC or whatever else.
My OD is Cobra...I've replaced the lower cable, bellows and impeller (several times) in all that time. Had the drive off a few times in between for inspections lubing, cleaning, etc. I think they're easier to work on that a Mercruiser. When and if it goes, I have a Volvo SX waiting - which is pretty much a Cobra with a Volvo emblem on it.
I've never had any problems finding parts, paying through the nose or finding someone capable of working on it.
The one issue I am going to run into soon is the cylinder caps. There are not available (unlike Mercruiser) - gotta spring for new (or used) cylinders.
 

Don S

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Re: OMC -what's bad - motor or drive?

The engine was used by OMC, and is still used by Merc and Volvo. The Cobra drives are ok, BUT. OMC went out of buisness about 10 years ago. Pars are basically aftermarket or used but readily available.
The biggest problem is repairs if you can't do it. Qualified techs for OD repair and adjustments with the special tools and know how are getting few and far between.

I have a Volvo SX waiting - which is pretty much a Cobra with a Volvo emblem on it
Not exactly. The inside of the Volvo SX drive is nothing like an OMC Cobra drive. It's cone clutch, so no shift interrupt system. You will need a new bellhousing and an engine driven raw water pump to convert and a new shift cable. Volvo makes a kit, but you won't like the price.
 

mthieme

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Re: OMC -what's bad - motor or drive?

I knew it was be too good to be true, but the price was right (free with less than 25 hours). I just stuck it in the back of the shed hoping I'd never need it - it's just the lower.
I was told it was a direct replacement. I guess that's relative.
But then I've also heard someone tell me an Alpha lower would "bolt up". I don't believe it.
I forgot about the Volvo water pumps. I had two of those this summer...maybe I should hang onto the next one that passes through!

If and when it ever comes time, I'll be bugging you like crazy.:D
I'm guessing I've just been lucky with mine.
 

packman35

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Re: OMC -what's bad - motor or drive?

Don - so do you think I could do any work on the drive/engine myself? I am quite mechanically inclined. I design/build/fix machines for a living (I'm an electrical/mechanical engineer) - just not much work on engines. I have my own limited machine shop so making the odd part or tool is not completely out of the question.

Or am I out of my gourd?:D
 

Gary H NC

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Re: OMC -what's bad - motor or drive?

With a factory service manual you can do most work on it.
Some will need special tools though.
Plan on spending at least 50 bucks on the manual...
What year is it?
 

Lou C

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Re: OMC -what's bad - motor or drive?

I agree with all of the above, I have had one for 7 years and outside of normal maintenance it's been pretty trouble free. I would call around and find out if there are shops that are familiar with them and can work on them, if not, it's really not a good idea unless you are really going to learn how to do everything yourself. I have the OE shop manual and do most of my own work but I have had to get the shop to re-seal it a couple of times, and to get the initial set up of the shift linkage correct. After that it was basically maintenance. There are so many boats out there, why not just buy whatever is most easily serviced? When you have an OMC it's like having a 35 year old classic muscle car, you have to search round for parts sometimes and people who know what to dowith them.
 

QC

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Re: OMC -what's bad - motor or drive?

Moved this over to I/O & Engine to help keep this good info where it belongs.

Not exactly. The inside of the Volvo SX drive is nothing like an OMC Cobra drive. It's cone clutch, so no shift interrupt system.
I have a question, Don. I thought Cobras were cone clutches from Day one?
 

packman35

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Re: OMC -what's bad - motor or drive?

Thanks guys for all the replies!!!

It is on a 1994 Sunbird 17 footer. It is a 3.0 Cobra. S/N T01273262

See my other post about the boat:

http://forums.iboats.com/showthread.php?t=286954

He wants $1500 for it is the reason why I am even considering it.

Also, believe it or not, boats in this area (Raleigh, NC) seem to be hard to come by in this price range. Lots of upside down loan boats but very few that are running and under $2K.
 

Don S

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Re: OMC -what's bad - motor or drive?

I have a question, Don. I thought Cobras were cone clutches from Day one?

This answer might help all you guys with the Cobras
OMC in their infinate wisdom named 3 totally different drives "King" Cobra.
One was the dog clutch type drive with the ESA system and the lower shift cable. This was used on all V8 engines started in 86.
Then came the OMC "King" Cobra. It had a cone clutch in the upper unit and went into production in 89 or 90 I think and had the raw water pump mounted on the outdrive like the dog clutch model.
Then around 94, OMC and Volvo went into a joint venture and the SX drive came about. Volvo called it the SX Cobra, but OMC called it the (you guessed it) "King" Cobra.
This drive has the basic out looks of a regular OMC Cobra drive in shape, but the insides are all Volvo cone clutch drive. NO raw water pump in the outdrive either. The shift mechanism for the drive is where the raw water pumps were located on the earlier Cobras. The pump was moved to engine driven on the SX drives.

The upper and lowers of the SX type drives are NOT interchangable with any OMC cobra drives
 

packman35

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Re: OMC -what's bad - motor or drive?

So as this is a 94 3.0, does that make it the SX drive? Is that better since it has the cone clutch? I hear the dog clutch was prone to breaking. Excuse my ignorance - totally new to this but trying to learn!!:)
 

Don S

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Re: OMC -what's bad - motor or drive?

Impossible to say. the engine package could be a year earlier. Boat year and engine/drive years may be different.
I can't tell you by SN, as I don't have any SN cross reference for OMC, but if you can find the spec number on the drive, it may help.
If the number starts with a 9XXXXX it's OMC, if it starts with a 3XXXXXX it's a Volvo. You can also check to see if there is an engne driven raw water pump. Or pull the back cover off the drive and see if there is a pump there or the shift mechanism.
 

Bondo

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Re: OMC -what's bad - motor or drive?

Excuse my ignorance - totally new to this but trying to learn!!
Ayuh,...

The Learning curve isn't all that Steep,....
This quote from Don is the Most Important statement in this whole Thread,...
Actually,... It pretty much frames the Whole, "Should I buy an OMC" Debate....
The Cobra drives are ok, BUT. OMC went out of buisness about 10 years ago. Parts are basically aftermarket or used but readily available.
The biggest problem is repairs if you can't do it. Qualified techs for OD repair and adjustments with the special tools and know how are getting few and far between.

Or am I out of my gourd?

eh, eh,...
I guess that's yet to be determined,.......:D
 

captmello

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Re: OMC -what's bad - motor or drive?

If that does have the SX volvo clone you could have found a good deal. Just don't let the boat owner know. Might be worth a return trip to check the numbers.
 

Lou C

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Re: OMC -what's bad - motor or drive?

The differnce in appearance is that the pure OMC Cobra built from 86-93 has a completely flat top cover, the joint venture OMC Cobras/Volvo SX Cobra had a bit of a hump on top. Here's a couple of pix:
If it looks like the pic on the left it's pure OMC, if it looks like the one on the right it's the OMC/Volvo joint venture drive.
 

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HT32BSX115

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Re: OMC -what's bad - motor or drive?

Howdy,

If it is indeed a 1994 model the housing will look like the picture below from Doug Russell and BRP

The list of parts has some items that are either "VINTGE" or "Please Call" etc.

That can mean "Unavailable" or Price: "Arm & Leg" in some cases.

It might be better to just say no unless someone is holding a gun to your head......:eek:

If I had it to over again I would not have took advantage of the "GREAT SWINGIN' DEAL" OMC King Cobra powered boat I bought from my brother a few years ago

(Which I then completely removed the eng/drive to replace it with a Mercruiser .... see my signature below)





ACF2379.gif






Just look for a VP or Merc powered boat. There's a LOT of people out there trying to sell them.


Cheers,



Rick
 
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