suzuki dt65 1990 on to an 18ft boat previously with an inboard

[zem]

hi not sure this is in the right topic but here goes, i have a suzuki dt65 1990 which i wish to install on to an 18ft searay boat which previously had an inboard engine. can this be done? if so what structual problems am i going to encounter? has anyone ever done such a thing? sorry for my lack of boating terms i have only bveen into boats for the last wk thanks for any help

 

[tashasdaddy]

Re: suzuki dt65 1990 on to an 18ft boat previously with an inboard

most who have done it, have not been happy with the results.

 

[erikgreen]

Re: suzuki dt65 1990 on to an 18ft boat previously with an inboard

In a nutshell that boat was not designed for that kind of engine.

To make it work on an inboard boat you will need to rebuild the stern of the boat to handle the outboard being there, which will involve most likely a complete transom replacement, plus the design and install of additional structure at the boat's rear to support the new transom. In order to install the transom you'll also need to remove the aft part of the deck and stringers and rebuild them afterward.

Then once the transom is ready you need to install the engine and rebalance the boat... the weight of the outboard will be much farther aft than the original engine's weight, causing problems with trim, which will make the boat hard to steer, hard to get on plane, and in the worst case may make it unsafe to drive until the problems are corrected, either by ballast forward or rebuilding the boat to move some weight forward.

Once it's balanced then you need to run all the wires, hoses, and cables to let the engine run, plus a steering system that will work with the outboard.

It's not a cheap and easy solution to put an outboard on a formerly inboard boat. It's much cheaper and easier to sell the boat or the motor and buy a better match.

That said, it can be done... it's just that most people who do it aren't happy with the result.

Erik

 

[SKIBUM1M]

Re: suzuki dt65 1990 on to an 18ft boat previously with an inboard

Excelent question and answer. I had never thought of trying it but erik had a great answer

 

[zem]

Re: suzuki dt65 1990 on to an 18ft boat previously with an inboard

hi thanks for the replies, as for rebuilding the end of the boat i think thats a bit too much for me to cope with, i have some strengthing solutions, i was thinking about installing some strenghthing brackets from the back of the boat to the old engine mounts which look very strong, this is hard to explain so i will post some photos with my ideas and any constructive critism will be appretiated, thanks again for the advice its been very helpful

 

[ondarvr]

Re: suzuki dt65 1990 on to an 18ft boat previously with an inboard

If you had been into boating for decades and knew exactly the boat and motor combination you wanted, and it wasn't available, then yes doing the conversion "may" be worth it. Since you have only been into boating for only a couple of weeks and know nothing about what you may (or may not) enjoy about it, plus having a motor that wouldn't even be a good match for that hull after the conversion, Id say its a very bad idea.

Find another hull that is set up for an outboard, it should cost you little or nothing, but will still need some work to get it on the water. Read about other projects here before buying or starting anything, plus go look at as many boats as you can (dealers, shows, etc). This will give you a better idea you may want, its very common for someone to think they want a certain type of boat only to find after a few months they don't like it and want something different. It will take you many months and a great deal of money to finish this conversion, and that's if you do finish it. After the conversion it won't be worth 1/8 of the money you have into it, let alone the labor.

 

[stylesabu]

Re: suzuki dt65 1990 on to an 18ft boat previously with an inboard

I agree with the other guys.this will be a lot of work. I too recently got into boating/fishing8 months ago I bought a 16' aluminum Sylvan w/ dt75 Suzuki,great motor by the way.My point is that I had been fishing with my buddy who has a 16' Sylvan w/90hp evinrude. I liked the size and the way it handled for what we do. So when it became clear to me that I needed my own boat, i had an Idea of what I wanted,the boat I bought runs great, but the deck was soft and i didn't like the way it was laid out. So I have sent the winter redoing the deck and the layout. It doesn't sound like you know want you want at this point. If you can afford it, buy the right hull for the motor or a motor for your in/ob hull.then down the road you'll have a better idea of what you might be getting into. i have been an auto tech most of my life and have retored many a car, some mods and some to orginal condition. the modified ones are always a pain in the *** and alot more work, and in the end usually not worth the effort. bottom line get more comfortable with boats before you take this on, a guarantee you won't save any money going this route. just my 2 cents.

 

[zem]

Re: suzuki dt65 1990 on to an 18ft boat previously with an inboard

thanks ondarvr for the advice, i am taking all this on board but im still gonna go ahead with it, i paid bout $800 for the boat with a decent trailer and got the engine for nothing so not much to loose, the engine needs some work (broken studd in the block) nothing major, so far as my untrained boating eye can see i need a steering cable some throttle and clutch cables a fuel tank and a life jacket. was just wondering what the main difference in the back of the boats was? obviously a boat made for an outboard would be stronger but what would make it stronger? and with the boat designed for the in board im sure there must be some strength back there, im gonna spread the load pretty much across the back of the boat, the worst case is if i put it in reverse the engine may pull the back of the boat off but im sure it cant be that weak....

 

[zem]

Re: suzuki dt65 1990 on to an 18ft boat previously with an inboard

sorry thanks styleabu good luck with ur project..

 

[zem]

Re: suzuki dt65 1990 on to an 18ft boat previously with an inboard

hi sorry to keep putting replys on here but is there anyone on here/or does anyone know someone who has done this??

 

[ondarvr]

Re: suzuki dt65 1990 on to an 18ft boat previously with an inboard

This type of project is done from time to time (some shops specialize in this type of work), but its normally done with a hull and/or brand that is high in value and the finished product is known to work very well. One of my current boats is a conversion and it works great.

The reason people are trying to steer you in another direction is because this boat is of little or no value, a non running 18' boat can be found very cheap, some people will even pay you to haul one away.

The motor you have is a non runner right now and an older Suzuki may be harder to find parts for, if it was a Johnson or Evinrude there would be no problem finding parts. Plus its not big enough for this boat, an 18' SR would be rated for around 135hp.

This adds up to several thousand $$$ in materials and no way of knowing if it will ever work, not to mention the year or so it will take you to finish it.

Find a hull designed for an outboard of this size if you want to use the Suzuki and then fix it up, but first make sure what you have runs. If it needs money put into it, buy something else.

 

[SKIBUM1M]

Re: suzuki dt65 1990 on to an 18ft boat previously with an inboard

On a related subject of things not designed for the purpose I have a question mostly for curriosity sake and possible use in the future. I have an automotive 351 windsor with an edelbrock cam, carb, and intake. Can this be used with an i/o setup or are the marine engines different? If they are different how so? and can it be overcome? I am happy for now with my outboard but at some point I want to get a bigger cuddy cabin to rebuild and I have the motor. My 15 foot is a little small when the lake gets rough.

 

[CheapboatKev]

Re: suzuki dt65 1990 on to an 18ft boat previously with an inboard

On a related subject of things not designed for the purpose I have a question mostly for curriosity sake and possible use in the future. I have an automotive 351 windsor with an edelbrock cam, carb, and intake. Can this be used with an i/o setup or are the marine engines different? If they are different how so? and can it be overcome? I am happy for now with my outboard but at some point I want to get a bigger cuddy cabin to rebuild and I have the motor. My 15 foot is a little small when the lake gets rough.

Skibum..
EDIT

Here is reading for you

http://forums.iboats.com/showthread.php?t=369284&highlight=what+makes+marine



Zem....
What is wrong with replacing the I/O that tub came with? If the hull is decent and your determined to keep her..A rebuilt replacement motor and drive would be best...

 

[erikgreen]

Re: suzuki dt65 1990 on to an 18ft boat previously with an inboard

It sounds like you're talking about an I/O, by the way, not an inboard (an inboard would have the prop under the hull, not on the back).

was just wondering what the main difference in the back of the boats was? obviously a boat made for an outboard would be stronger but what would make it stronger?

What makes it stronger is the fact that the transom is thicker, more heavily reinforced and bonded to the hull, and usually knees (triangular braces) attach the transom to the stringers. You can reinforce your transom some, but unless you either replace it with something thicker or layer another thickness of fiberglass and wood on top of it and then add the bracing you're talking about, it won't be strong enough. Hence my comments about rebuilding the transom.

and with the boat designed for the in board im sure there must be some strength back there, im gonna spread the load pretty much across the back of the boat, the worst case is if i put it in reverse the engine may pull the back of the boat off but im sure it cant be that weak....

Actually it can. Depending on the condition of the existing transom (if it's rotted at all) the first time you reverse (or for that matter throttle up in forward) the engine can twist off its mounts and fall in the water. It's happened to people with bad transoms.

An inboard transom is weaker than an I/O transom which is weaker than an outboard transom. The I/O transom has the sterndrive running through it and bolted to it which takes some force, but doesn't hold up the weight of the engine. The outboard transom absorbs all the force of engine thrust, holds the engine block in the air no matter how the boat tips/tilts/stops, and also transmits all that force to the rest of the boat.

I know you're looking for someone that's done this sort of job, and there are a few people around here who have tried it or done it. But some of the most expert folks on this board have replied to you.. they've seen this done in their shops or by friends, and are giving you their best advice. If you're determined to do it, we'll help and comment (post pics). Maybe if it works for you and you do a great job you'll change some minds. Or, maybe not.

It CAN be done... cheaply or safely, pick one. I encourage you to not sacrifice safety. I know it just doesn't "sound right" when people say you can't do this and have it work well, but intuition can lead you astray sometimes.



Erik

 

[SKIBUM1M]

Re: suzuki dt65 1990 on to an 18ft boat previously with an inboard

Zem, There were neighsayers when Oops started his thread of extending his boat, however he was not new at boating. I realize you are sitting there with a boat and a motor looking at them and thinking of getting out on the water. There is a way to get out on the water that would most likely not cost you anything and take much less time. Check craigslist for an outboard hull that someone is giving away, if there is no luck there put an add on it asking for a free boat or offer a little cash. You would be supprised how eager some people would be to get rid of that big eyesore in the backyard. As a last resort drive around and look for a boat that looks very unused then knock or leave a message asking if they want to sell it.

 

[CheapboatKev]

Re: suzuki dt65 1990 on to an 18ft boat previously with an inboard

I agree with you 100% on Oops extending his hull and all of the YOU ARE CRAZY comments..That was an excellent comment and well placed.

 

[stylesabu]

Re: suzuki dt65 1990 on to an 18ft boat previously with an inboard

Zem, by the way my boat does about 38-39 mph per gps on calm water no wind.It wasn't this way when i bought it, but though the help of the prop master hwsii in the prop section between getting the right prop and the right motor depth mount I was able to pick up another 2-3 mph. I can keep up with my buddy's 90 hp same hull, if I wax the hull this spring he may be chasing me.i'm just trying to help you get an idea of how fast your boat my go, myself i don't really care 35 or 40 mph, its all about getting on plane with the wieght i must carry to get to where i fish. Good luck,but I think you can find a hull for that motor,alot cheaper that taking on what you're proposing.again just my 2 cents, as an auto tech i always had apprentices asking what was the "short cut" to ant job they were watching me do, I always told them do it by the repair manual first and youi will figure out your own tricks. put a boat together the way it supposed to be, it will give you sooooo much more insight as to how to modifiy, which is what your attempting. that said there were a couple of engine i install in ford vans that at the time i was told could be done. i did it had some problems but I WAS ONLY 17 AT THE TIME

 

[stylesabu]

Re: suzuki dt65 1990 on to an 18ft boat previously with an inboard

please excuse poor spelling,1, ok 3 too many beers.

 

[ezmobee]

Re: suzuki dt65 1990 on to an 18ft boat previously with an inboard

On a related subject of things not designed for the purpose I have a question mostly for curiosity sake and possible use in the future. I have an automotive 351 windsor with an edelbrock cam, carb, and intake. Can this be used with an i/o setup or are the marine engines different? If they are different how so? and can it be overcome? I am happy for now with my outboard but at some point I want to get a bigger cuddy cabin to rebuild and I have the motor. My 15 foot is a little small when the lake gets rough.

Start a new thread in the I/O forum. Those guy's are guru's in this area.

 

[zem]

Re: suzuki dt65 1990 on to an 18ft boat previously with an inboard

hi dont worry bout the thread hijacking its fine, im just wondering if any one knowa the best place to purchase a 12 inch set back jack plate? thanks