OMC - Swap engine and stern drive

horseflysc

horseflysc

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I'm new here but after a week of looking I haven't found a post really related to my question. Here goes but with some info 1st. I recently aquired a 18' (1982) bowrider. It is in excellent shape having been under covered storage much of its life. All except the engine/drive. It has a OMC 3.8 with a 800 series mechanical shift stern drive (model 983159). The engine is not completely froze but is hard to turn. I have no experince with I/O setups, only smaller <90hp outboards. Thinking about costs I wonder if I should just replace the whole system motor+drive with (1)another compatible system, (2)have it all rebuilt, or (3)Rip it all out and install a transom outboard bracket and outboard engine.

Any ideas on what would be compatible as a replacement? Info I can find says this thing is rated at about 140hp.
 
Don S

Don S

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Re: OMC - Swap engine and stern drive

You really picked the wrong kind of boat to do anything with. Changing to something like a Mercruiser isn't that easy either. The transom is too thin, and depending on the stringers in the boat, they may be in the wrong place.
Sticking with what you have is about the only option, but the 3.8 was another thing that just wasn't used very often. So finding a rebuilt engine may be problematic depending on your location.
The other thing is OMC went out of business about 12 years ago, so finding techs to fix things you can't could also be a problem.
The stringer drives (800's and 400's) are another thing long gone. Last used in 85, over 25 years ago. Lots of aftermarket parts available, at a price, and many of the housings that corrode away are only available used if you can find them.
So before you throw a lot of money at it, think about what you will have when you are done. If you get everything fixed for a few thousand in parts, you still have a boat that won't sell for near what you have in it.
 
horseflysc

horseflysc

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Re: OMC - Swap engine and stern drive

Thanks for the info. From what I have found the 3.8 is a 229cid V6 chevy engine and the parts are available everywhere for rebuilding/maintenance. So I don't think the engine will be a big issue.
That being said, the 800 stringer drive really concerns me. I see them avialable as rebuilts on the Net and they are quite pricey. I know about engine rebuilding but I don't squat about a stern drive.
I wonder if any other drives would fit. Be nice if there was a compatiblity/cross reference chart for marine like there is for auto parts!

As for the resale, that doesn't worry me too much since I spent only a few hundred $ for the boat and even if I put several thousand into it I won't have the $20k+ for a new or late model boat that they would cost.
This way I can keep the $ away from the tax man here in SC and insurance will be less also.

By the way the transom and stringers look pretty beefy in this thing - even more so than some new ones I have seen at boat shows. Nice 29 year old fiberglass (everything on this boat seems heavier/thicker).
I have a friend whose son is a marine mechanic and I think I will get him to evaluate it for me before I go dumping $ into it.
 
H

HT32BSX115

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10,083
Re: OMC - Swap engine and stern drive

I spent only a few hundred $ for the boat and even if I put several thousand into it I won't have the $20k+ for a new or late model boat that they would cost.
Click to expand...


Howdy,


You might be far better off just parting it out. you could probably sell the engine and drive parts etc for more than you paid for it.

"several thousand" Will actually get you a pretty nice boat with a much newer engine/drive made by a company that is still in business.


Regards,


Rick
 
Bondo

Bondo

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71,095
Re: OMC - Swap engine and stern drive

I wonder if any other drives would fit.
Click to expand...

Ayuh,.... NOTHING interchanges with that Motor, or that Drive....

You're at this point starring into a bottomless abyss....

Turn, 'n RUN just as fast as you can....
I'm tellin' ya,... You want Nothing to do with that boat.....

You can buy a Running boat for about 1/2 the ca$h yer gonna Dump into that Bottomless Abyss....
 
horseflysc

horseflysc

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Feb 8, 2011
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Re: OMC - Swap engine and stern drive

So what everyone is telling me is that even though I have a perfectly good boat minus the engine and drive, I just need to part with it and go with another? Hard to imagine since all I need is a engine (115 - 140HP) and a drive. I know those make up 1/2 or so the price of a new boat but with another used boat I may stilll need to carpet, recover seats, etc - and still have motor/drive work to do. If I spend $6-7K on this there is no way I see that I can find something 1/2 that amount or even close to that that is in good running shape while the rest of the boat is in this great of condition. Maybe I'll sit on this a few weeks before doing anything rash. Thanks all for the info.
...
 
W

wire knot

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Aug 24, 2006
Messages
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Re: OMC - Swap engine and stern drive

If you got a good boat ya like.....put some Merc or volvo stuff in it, you'll be fine. People do it all the time.
Most say get a donor boat, already with controls, guages, etc.
Or get new, remember on an '82 OMC the transom hole is much larger than anything new, and will have to be
filled in.
I just repowered a '75 Mako that had a OMC powerplant, you gotta want it real bad( otherwise known as $$$$$$).

WK
 
Don S

Don S

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Re: OMC - Swap engine and stern drive

remember on an '82 OMC the transom hole is much larger than anything new, and will have to be
filled in.
Click to expand...
Not only is the hole bigger and has to be filled in, but the transom for a Merc or Volvo has to be between 2 and 2-1/4" thick instead of the standard 1" thickness of the stringer transoms.
 
horseflysc

horseflysc

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Re: OMC - Swap engine and stern drive

How thick does the transom need to be to support an offset transom bracket and OB motor? I thought about rebuilding or beefing up the transom and just hanging a outboard off of that. This would reduce the weight by about 600lbs with the exception of the weight added by the materials to stregthen the transom. Looking at a 115hp to about 130hp to use for power....
 
Don S

Don S

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Re: OMC - Swap engine and stern drive

In General,Outboard transoms are thicker than IO transoms
You might want to post that question over in the Restoration/boat building forum..
Installing transom brackets and outboard motors isn't covered here in the IO forum.
 
horseflysc

horseflysc

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Re: OMC - Swap engine and stern drive

Ok so I've done all the studying and all that I think can be done actually can be done w/o breaking the bank (but serious dents will occur). I'd love to tackle this project just to see if I can do it but I'd rather be out on the water this year instead of next. Next question (direct me to another forum if necessary): I can't have 2 boats (plus my 30' camper) sitting out in my yard (HOA says 1 boat, 1 camper in back yards) so I need to move this as fast as possible, preferably for a few hundred $. What avenues would any of you suggest? Can't get another boat until this one is gone. Will be a high of 73 here on Friday-Sunday so I'm itching for a running boat!
Thanks All for bringing me to my senses (even tho the wife disagrees).
 
raymondpickens

raymondpickens

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Re: OMC - Swap engine and stern drive

I have an 82, wellcraft 160 with yes the 3.8 omc stringer. Boat is in excellent structural condition, seats have cracked some but it has been garaged since new (it was my dads and he never used it). Other than dust and motor and drive that I cant get ANY mechanic to touch without laughing and saying how big is your checkbook,and how much time do you have. I agree with finding another boat as hard as that is to do when you have a perfectly good hull sitting in the garage.
 
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