MCM 140 in place of an OMC 140 990244s1 and have it bolt up to outdrive 983486 ???

[JeffKingTulsa]

Have an OMC 140 that started to make a knock and wondering if I can take a good MCM 140 and put it in place of the OMC 140

 

[Bondo]

Ayuh,..... The Long Blocks are the Same,.... The Bobtail motors are Not the same,.....

The bolt holes won't line up, nor the plumbin', nor exhaust, nor anything else,....
What does line up, will be a different diameter,....

 

[JeffKingTulsa]

Thanks for the info. How/where can I find a list of engines that I can look for that will fit? Tired of fighting that thing over the years and just want something solid that works well. Afraid if I try an engine rebuild kit it will just be the same old same old. Have 90 lbs compression in the back 3 cylinders and 60 in the front. Thought maybe threw a rod but compression is there. Pulled valve cover and everything looked ok. I am guessing that I need to just find another motor to drop in but where and what is compatible is the question.

 

[southkogs]

How big a boat and what HP are you rated for?

 

[JeffKingTulsa]

It is an old 28 foot aluminum double deck pontoon. Maybe an old Lakes Craft. ( A boat yard in Georgia pieced it together ) Not sure what the HP rating is max.

 

[JeffKingTulsa]

http://www.vivaboats.com/advert/lakes_craft_28_omc_140_pontoon_boats/3728

Here is the link and people I got it from.

 

[southkogs]

I don't know the first thing about aluminum work ... so take this CAREFULLY ...

IF you're up against a re-power, and it's not too much more money to convert the stern ... consider going to an outboard or a Mercruiser system at this point. The Merc would be easier to service in the long haul and toons tend to lend themselves to work well with outboard power pretty well (that's what most of 'em are).

Any shops close to you who can quote ya' on the transom work?

Have you already bought this?

 

[JeffKingTulsa]

Yea, I have had it for about 3 years and replaced almost everything outside the motor... sigh....

 

[southkogs]

Oh wow! That's cool. Hey it's a 'toon ... those are about the best things in the world to have problems with. You have a ton of options. And to be honest, rather than pouring a ton of money and time into a Stringer, I'd shift my time and money into a conversion. Probably comparable time, energy and cash and a better long term outcome.

 

[JeffKingTulsa]

oh its a super cool boat. love it no doubt, just short on time and tired of the fight. Shop has a MCM 140 that is good. I'm confused. Another boat guy says all the core of the engine is the same and I can just bolt my exhast manifold and flywheel to it and use it? Idk, about difference in motor mounts but on here they say no go??? When I researched motors I found this place that seems all about to sell me what appears a standard ready engine. Here is the email..
[FONT=&quot]Thanks for your inquiry and the opportunity at earning your business. Using the links below you can review available option regarding the 3.0L repowers. Let me know if you need any further technical information or help placing your order. In either case I will be glad to assist![/FONT]
[FONT=&quot] [/FONT]
[FONT=&quot]Link to 3.0L Longblocks[/FONT]
[FONT=&quot][FONT=&quot]http://tinyurl.com/anas6qx[/FONT][/FONT]

 

[JeffKingTulsa]

I'm lost on the difference between the MCM 140 and these they would sell me and mine....

 

[southkogs]

If I'm not mistaken: there's some confusion around that engine because it get's confused with the "Iron Duke" motor, and it's not the same (153cu vs 181cu, I think). I'm not familiar enough to know. From Bondo's post, the long block should match up if I follow him right.

That said: You've got a hydro-mechanical shift OMC Stringer. It's a booger of a system to keep alive, particularly if the shift system goes belly up on ya'. Since you're looking at $3k into power, I would (personally) look to put that $3k into something more modern and serviceable. OMC is gone and some of the parts to a Stringer are NLA. You can keep 'em going, but you're at the right point and place to bag it and go to a more modern system.

I personally wouldn't put $3k into a Stringer (as much as I like my boat). I'd consider finding a used outboard that suited me and spending the money on converting the transom on a pontoon.

 

[Bondo]

I'm lost on the difference between the MCM 140 and these they would sell me and mine....

Ayuh,.... The differences are in yer understandin' of motors,....

The Long Blocks, are the same,....
A Long Block motor is the internals, the block, 'n head,....

The Bobtail motors, while built on the same Long Blocks, are Different,....
A Bobtail motor, is a fully dressed, drop-in, plug, 'n play motor,....

Of the Bobtail motors, the MCM is built with Mercruiser accessories,....
You need to replace yer Long Block, 'n dress it with yer OMC accessories to fit into yer boat,....

All that said,... I Completely agree with Southkogs,.....
Buy a rotten boat with a solid driveline, say a 3.0l Merc/ Alpha, or a 4.3l Merc/ Alpha, 'n drop it into yer boat,....
After the job is done, yer boat oughta good for another 20 years,...

 

[JeffKingTulsa]

No Title

Good morning ya water dogs!
I hear ya on it would be nice. I am not sure 3 grand is in the budget. Goal is to just get back out on the water and running for another summer. Boat was $5000 and they ripped me off something fierce on this scissor jack trailer for $2700 so another 3 to 4 grand seems a little much into it. He has this motor sitting there and it is supposed to be good. Seems like if I could just take my flywheel, see if my motor mounts bolt up, if it bolts up to the intermediate housing and exhaust manifold, leave ignition, wires, plugs, distr, carb, water pump/pulleys in front, fuel pump. Why not do that? Unless someone is saying this plan wont work. Then all I need to do is either put my other lower unit on ( Hopefully Pete still has it ) that will replace some worn clutch dogs, check the impeller in the upper drive for water flow and away I go down the road.

 

[southkogs]

If you've got a motor for nuthin' (or next to nuthin') looking for a place to go, then yeah - bolt it up. The link to the engines you sent had the engine cost at $3k, that's where I got the number from. $500 or below - if the OMC still runs, I'd take that chance.

But, like Bondo said, you can find an old boat that's been neglected with a reasonably good Mercruiser set in it. And you can probably find that somewhat cheap. If you're heading much north of $500 or so, I'd start looking at other options.

 

[Bondo]

Seems like if I could just take my flywheel, see if my motor mounts bolt up, if it bolts up to the intermediate housing and exhaust manifold, leave ignition, wires, plugs, distr, carb, water pump/pulleys in front, fuel pump. Why not do that? Unless someone is saying this plan wont work.

Ayuh,.... As I've already said, the Merc dressin's on the motor, are NOT a direct swap for the OMC dressin's on yer motor,....

The intake, 'n exhaust are Different,... Alignment won't happen, carb linkages won't fit,...

The ignition, most likely won't play well with yer drive,....

The fuel pump, may, or more likely is Not the same, just close,....

The circulatin' water pump, 'n pulleys probably are the same,....

With both motors sittin' side by side on the floor, there's enough parts to make it work, but most of the Merc stuff, Ain't gonna be used,...

 

[JeffKingTulsa]

No Title

UPDATE:

Thanks gents for all the info and help. Turns out the MCM 140 block was trash and my mechanic whose shop and tools I get to use doesn't work on anything that a transom has to be modified for "legal reasons" so this is happening. Pulled the engine and tore it down to the long block at have it to a southwest motors shop around Tulsa here to get rebuilt. Now onto the stern drive ( new post ) for now..