need advice on how to power my boat

angie1015

Petty Officer 3rd Class
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Aug 21, 2006
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Just put a deposit on a 1984 larson delta 25' with the nice size cabin sleeps 4 bathroom, shower, camper top the whole nine yards. the boat is in absolute mint conditon and was in fresh water its whole life. came with trailer. problem is the motor knocks so i got it for 3 grand. for some reason the boat has a 305 chevy motor. i dont know how many horses however the boat cruises at 17 mph and tops out at 25ish. not fast enough for me. I want to replace the motor with a 350/350 horse. i want to make sure that this swap will be worth my time. will this boat ever hit 40 and cruise at 30mph with a 350/350?? also its a omc outrive which i am told over and over again to stay away from. I might be wrong but i thought that an omc drive would be a ford motor but this one i think has a chevy. the firing order and the GM stamp on the intake manifold would tell me chevy. I never heard of a chevy motor and an omc drive.. could that be original? is 3 grand a good deal for an 84 larson 25' delta w/trailer?? i am new to boating . here is a link with the pic..http://www.bargainnews.com/viewad.cfm?Show_Notepad=Yes&bnAd_ID=6364981&TheDealer=
 

aerwin

Petty Officer 2nd Class
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Mar 28, 2002
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192
Re: need advice on how to power my boat

run don't walk away from this deal, yes O.M.C. used alot of g.m. engines, I have the exact same set-up but on a smaller boat, the 305 is great but the sterndrive is not. its ok when it is working good but when it comes time for parts and stuff it's getting tougher to get certain parts and they are getting expensive. A 350 will work but that is the most that that outdrive will handle and the gain won't be what you want, you need at least a 454 with a heavier duty outdrive like a bravo or a king cobra, your looking at minimum of 7000.00 for the very time consuming change over, not worth it in my book, get a different boat!
 

whywhyzed

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Feb 1, 2005
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Re: need advice on how to power my boat

If the trailer came with it, you're ok at $3000, but yes if you can get out of it and find a Mercruiser powered first boat, you'll be better off. I like OMC's. Just start looking for a spare drive and read all you can about the tilt clutch system.
Yep, a 70's or early 80's Chevy 350 long block will swap in.
The 350 with a 4 bbl carb will give you 260HP
That outdrive can only handle 260HP.
The 305 is rated at 230 or so with a 4BBL.
It will never hit 40, no....
About 90% of OMC setups use Chevrolet engines.
 

Bondo

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Re: need advice on how to power my boat

kjdkjd said:
yes if you can get out of it and find a Mercruiser powered first boat, you'll be better off.

Ayuh,..........

This is the kinda Deal that will make You a Bankrupt Former Boater in a Hurry.........

Run,...... Run Away from that old OMC Just as Fast as you Can..........
 

angie1015

Petty Officer 3rd Class
Joined
Aug 21, 2006
Messages
83
Re: need advice on how to power my boat

thanks for the advice guys. one thing i forgot to mention is that i have a guy who gets 350 marine engines for about 1500 bucks out of the box and i do all the work myself. so for about 4500 bucks give or take i have this boat complete. does that change anybodys opinion.
 

tashasdaddy

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Re: need advice on how to power my boat

the engine is not the problem, the omc out drive is.
 

aerwin

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Mar 28, 2002
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192
Re: need advice on how to power my boat

You just cannot swap the stringer outdrive for anything modern, first a big hole to fill, all new controls meaning stering and throttle, new engine location, back a few inches, a whole new outdrive, from engine back, no matter what you do, it will be way more than 4500 unless you get a whole donner boat that has all of the stuff you need, the omc stringer was an odd-ball as far as the hole in the boat, I would love to do the conversion also but my $3000.00 boat is not worth it, a boat is pretty much worthless without the engine and outdrive, start runnin
 

Don S

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Aug 31, 2004
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62,321
Re: need advice on how to power my boat

angie1015 said:
thanks for the advice guys. one thing i forgot to mention is that i have a guy who gets 350 marine engines for about 1500 bucks out of the box and i do all the work myself. so for about 4500 bucks give or take i have this boat complete. does that change anybodys opinion.

Doesn't change my opinion, but it does explain why you are wanting to do this.
You really don't have a clue about marine engines and drive systems, or the differences between marine and automotive.

Sorry to be blunt, but you ask for it.
 

Reel Poor

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Jan 29, 2005
Messages
5,522
Re: need advice on how to power my boat

I agree with the rest of the posters.......Get your deposit back and find a different boat. If you find a boat in your yard with an OMC drive......."Move".......Thats the only way to get rid of it.
 
D

DJ

Guest
Re: need advice on how to power my boat

It takes one heck of allot ponies to get a boat moving from 25 to 40 MPH. You can those ponies out of a small block (Ford or Chevy) but as the others have stated, the drive can't handle it.
 

angie1015

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Aug 21, 2006
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Re: need advice on how to power my boat

You just cannot swap the stringer outdrive for anything modern, first a big hole to fill, all new controls meaning stering and throttle, new engine location, back a few inches, a whole new outdrive, from engine back, no matter what you do, it will be way more than 4500 unless you get a whole donner boat that has all of the stuff you need, the omc stringer was an odd-ball as far as the hole in the boat, I would love to do the conversion also but my $3000.00 boat is not worth it, a boat is pretty much worthless without the engine and outdrive, start runn...




what do you mean. i am not swapping the drive. the drive works fine it was rebuilt 3 years ago for over 2 grand. its the engine want to swap. if i cant but a 350 horse cause my drive wont handle it then... ill just get a 260 horse and hopefully i can cruise close to 25mph.

in response to don s... why do u say i dont know aboutmarine engines. i have rebuilt a few and done engine swaps before. please explain what you mean..
 

tashasdaddy

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Re: need advice on how to power my boat

go ahead and do it then, just remember you have been fairly warned about the obsolesence of the outdrive. it may last a few weeks or a few years. good thing you know about wrenches. in the future you may be rebuilding the transom and stringers to accept another power train.
 

Bondo

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Re: need advice on how to power my boat

Ayuh,.........

That $4500. is going to turn into $5500. or More before you go Boating...........

And,......

You'll Still own a $2000. Boat.............. Period.........

There are Millions of Great Project Boats out there,...
Especially This time of Year,.....
Go find yourself 1 that Doesn't say OMC on it,.... Anywhere.......

Then go have a Good Time..........
 

aerwin

Petty Officer 2nd Class
Joined
Mar 28, 2002
Messages
192
Re: need advice on how to power my boat

angie1015 said:
You just cannot swap the stringer outdrive for anything modern, first a big hole to fill, all new controls meaning stering and throttle, new engine location, back a few inches, a whole new outdrive, from engine back, no matter what you do, it will be way more than 4500 unless you get a whole donner boat that has all of the stuff you need, the omc stringer was an odd-ball as far as the hole in the boat, I would love to do the conversion also but my $3000.00 boat is not worth it, a boat is pretty much worthless without the engine and outdrive, start runn...




what do you mean. i am not swapping the drive. the drive works fine it was rebuilt 3 years ago for over 2 grand. its the engine want to swap. if i cant but a 350 horse cause my drive wont handle it then... ill just get a 260 horse and hopefully i can cruise close to 25mph.

in response to don s... why do u say i dont know aboutmarine engines. i have rebuilt a few and done engine swaps before. please explain what you mean..



putting 260 horses on a drive that will only handle 260 is asking for trouble, running max on it will wear it out quickly and break things, these drive have to be pamperd as it is, I will never do full trottle or make sudden throttle changes on mine and mine is only a 185 horse 305, mines gotta last for a while, and I'm a young kid that loves speed, "get a different boat"
 

aerwin

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Messages
192
Re: need advice on how to power my boat

I wish I had that kind of advice when I bought my boat, I bought mine right before o.m.c. anounced bankruptcy. the boat was real nice and ran great, even the outdrive worked good but in time I have had it of 2 times for repairs, water pump shaft and seals. I am borrowd time with the shift cable, I need to find one soon, $350.00 for a lousy cable. just knowing that the drive is the weakest point of my boat is enough to make things a little scary on the water. Would you buy a car knowing that the manufacture doe'snt exist anymore? just parts that are left over (and a few after market) are all thats there, I wouldn't
 

angie1015

Petty Officer 3rd Class
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Aug 21, 2006
Messages
83
Re: need advice on how to power my boat

kjdkjd said:
If the trailer came with it, you're ok at $3000, but yes if you can get out of it and find a Mercruiser powered first boat, you'll be better off. I like OMC's. Just start looking for a spare drive and read all you can about the tilt clutch system.
Yep, a 70's or early 80's Chevy 350 long block will swap in.
The 350 with a 4 bbl carb will give you 260HP
That outdrive can only handle 260HP.
The 305 is rated at 230 or so with a 4BBL.
It will never hit 40, no....
About 90% of OMC setups use Chevrolet engines.





wow thats perfect information thank you for you help. its sad that some people on these boards like to take the opportunity and just rip apart any question. if i knew enough about boats i wouldnt need this site. anyway thanks for your help. thats what this site is all about.
 

angie1015

Petty Officer 3rd Class
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Aug 21, 2006
Messages
83
Re: need advice on how to power my boat

kjdkjd said:
If the trailer came with it, you're ok at $3000, but yes if you can get out of it and find a Mercruiser powered first boat, you'll be better off. I like OMC's. Just start looking for a spare drive and read all you can about the tilt clutch system.
Yep, a 70's or early 80's Chevy 350 long block will swap in.
The 350 with a 4 bbl carb will give you 260HP
That outdrive can only handle 260HP.
The 305 is rated at 230 or so with a 4BBL.
It will never hit 40, no....
About 90% of OMC setups use Chevrolet engines.



i find it interesting that you say the 305 is rated at @ 230 horse. i have been shopping around and found the identical boat with a 350/260 horse runs about 25mph cruse and 35 max. how could only 30 extra horse add 10 mph?? this boat cruses at about 17 and max about 25 seems a little low even for this boat. if i did get this boat i might be better off just rebuilding the 305 rather then buying a brand new 350 just for 30 horses.

also everyone has been trashing the value of this boat cause of the omc drive. not that this matters but the drive was totally rebuilt in 2001 and used a handfull of times sense then. i have all the papers it cost almost 2 grand to rebuild. should i not have at least a couple of years before i have to worry about the drive.... ??
i have never seen a boat in better shape then this one and i looked at boats 15 years newer. correct me if i am wrong but brand new exhause manifolds out of the box and a 25 foot steel trailer is worth more then the 3 grand that i would pay for the boat. the full camper canvis is more then 2500 bucks as well. dont get me wrong I am not trying to question anyones great advise however if i get three years out of this boat and then have to pay 2 grand to rebuild the drive again is that a bad thing. if i wanted this size boat complete ready to go with or without a merc drive im looking at spending over 8 grand. and will that boat be in the new conditon that this one is?? if anyone can tell me whre i can get a boat mint condition not a mark on the hull, a cuddy that looks like it has never been used, a full head w/shower, sink, stove, trailer ect for anywhere close to 3 grand then i am all ears.....
 

angie1015

Petty Officer 3rd Class
Joined
Aug 21, 2006
Messages
83
Re: need advice on how to power my boat

kjdkjd said:
If the trailer came with it, you're ok at $3000, but yes if you can get out of it and find a Mercruiser powered first boat, you'll be better off. I like OMC's. Just start looking for a spare drive and read all you can about the tilt clutch system.
Yep, a 70's or early 80's Chevy 350 long block will swap in.
The 350 with a 4 bbl carb will give you 260HP
That outdrive can only handle 260HP.
The 305 is rated at 230 or so with a 4BBL.
It will never hit 40, no....
About 90% of OMC setups use Chevrolet engines.



one more quick thing.. you say late 70's early 80's 350 would fit. what about a brand new one?? say from jaspar marine engines. crate engine... does that not bolt up the same??
 

Bondo

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Staff member
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Messages
70,465
Re: need advice on how to power my boat

You came here Looking for Advise,.......

Being an OMC, Stringer drive boat,.....
You've gotten Alot of Good,... No make that Great Advise........

Your reasoning is Flawed,.... just because $2000.00 was spent on the Outdrive means Absolutely Nothing as to whether it'll run for a Hour, or a Season, or maybe 2......

The Reason this boat is Offered Sooooooo Cheap is Because it's OMC powered with a Stringer Dive........

If you decide to Buy it,...... You're Still going to Spend that $8000.00,.....Maybe not in 1 Pile,......
But you WILL be Spending it...........

If you want to be a Boater,........ Buy a Different Boat...........

If you'd rather Work on Boats,........ Go ahead,+ Buy it.............

But,........
When you return to iboats, explaining All your Problems,............
Rest Assured,...........

We Will be saying,......... We Told You So..........

You're a Newbie Boater who Doesn't Know much about Boats,.........
We're Trying to give you a Fast Education,......
But if you Refuse to Learn,................................................................:/

Btw,...... That $2500.00 Camper Canvas is Pretty Much Worthless,........
Unless you could find someone with That Exact Same Boat,.......
Who wanted That Exact Same Color..........
 

aerwin

Petty Officer 2nd Class
Joined
Mar 28, 2002
Messages
192
Re: need advice on how to power my boat

bond-o is right,

just because it was just rebuilt don't mean its gona last, were not ripping o.m.c. just experianced, remember would you buy a car from a manufacture that is out of business? parts at 2000.00 a year ago might be 6000.00 in two years for that drive or non availiable.

my boat was in excellent shape also when I bought it but when the outdrive goes out and no parts availiable then it worthless
 
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