converting from outdrive to jet

[tooslow]

I own a 1990 Ultra 21ft. I built a 383 sbc with an alpha drive, and am not pleased with the results. I have only owned jet boats in the past, and am considering pulling the motor and drive and replacing them with a big block and jet drive. Anyone tried this at home? I've been told that there is a template for mounting the jet, and am curious as to how difficult the project may be. Any suggestions?

[jroos]

What I would do is subscribe to Tractor Pull Mag and see how much room (and how many engines your hull can still float) and see what there techs advise. ~cause what tha hey I personnally bench race, ,,,,,every now and then!
Gotta love,,,,,,,,,Awe` hell ya`ll know tha drill.

[tooslow]

Is there anyone out there with a serious reply. Jroos- I'll send you some pics of my boat, and if you're interested, the motor and drive will be up for sale when the project is completed. I spoke with the techs at Tractor Pull, and they said you had snagged up the last subscription....

[Hallett19]

anything is possible, why don't you get a hold of the manufacture to see what they say, but I honestly think it would not be worth it, why do you want to do it anyway ? is it not fast enough ? from what I have heard, everyone with a outie likes the way they go. what is it you arent happy with anyway?

[Hallett19]

oh, a little addition to that, I am sure outies are great but I love my jet baby !!!

[tooslow]

I am looking for more speed. My boat did 52mph in stock trim, with the new motor I only picked up about 3mph. My last boat was a carrera eclipse with a 454 and berkeley jet, it did about 63mph. I think I can convert to a jet with a big block cheaper than a bravo drive with a big block. I too loved my jet, but I was looking for a bigger boat and found a good deal on this one.

[Hallett19]

well, after buying an engine and a pump and IF you do all the work yourself, you will still be in it at least 5 grand, and that is with used parts, new parts and having someone do the work for you, I am sure you are looking at $$$$$$$$ upwards of 10 grand

[flat broke]

tooslow,
Look up Ultra28 on this board. He should be able to let you know how feasible it is to do the swap since he is pretty familiar with Ultra hulls http://free.***boat.net/ubb/biggrin.gif Personally, if you like the boat you have, then there is always a way to pull off what you want to do. If you were to abandon the traditional berkeley transom adapter you would be able to cover the hole left by the Alpha cutout for sure. Since you're going to be cutting a fresh hole in the bottom, might as well set her up for a set back pump and try and reclaim some of the interior space you are going to forfeit to the BBC and pump. If you don't get a hold of Ultra28, give Jack McClure at MPD a call. (949-631-2040 or jmcclure@pacbell.net) He'll shoot straight with you and could probably get you heading in the right direction quickly.
Good luck,
Chris www.liquidaddiction.net (http://www.liquidaddiction.net)

[tooslow]

Flat Broke,
Thanks for the advice, I'll give him a call and see what he has to say, I appreciate the help. Is the 12JE or 12JY a setback pump? I have access to one, I think its an E, and is partly why I am considering the change. Also what mods can be done to the pump for more performance? Is a stainless impeller necessary? I am going to try a bigger cam and some carb adjustments in my current set up, but if it doesn't improve much, I will probably do the conversion
[This message has been edited by tooslow (edited January 27, 2002).]
[This message has been edited by tooslow (edited January 27, 2002).]

[future boater]

too slow ,
post a topic saying attention ultra 28 or question ultra 28 or something along those lines. he will answer your question within a few days. if anyone knows he will, sice he owns ultra. hows that for customer service?

[RiverDave2]

TwoSlow, Generally a small block with an I/O is about as fast as a big block jet in the same hull. You might be better suited upping the horsepower and being gentle on the alpha.. If not there are alot of guys selling rebuilt bravo's pretty cheap and there good for 5-600 horsepower in which will take you faster then you want to go in a 21 Ultra.
RD

[fat rat]

Why not sell the boat.....the market should be good for what you have and buy a jet......I think you would be $$$$$$$$ ahead. My $.02. Good Luck

[HYDROMOBILE]

Tooslow, You treat the boat like a new one after you pull out eng and outdrive, I would get a intake with a ride plate and shoe.set it back, instead of berk transom adpt. you make a template of cardboard in two pieaces to cover the hole in transom and seal the jet, like a race boat. then trace the card board onto a piece of alum cut it out bolt it to the transom with a lot of silicone. that will give you about the same interior room as you have now, polish your new transom plates or anodize them it will look as if it was made that way. Jim (818)890-1867 cyclone speed & marine

[Slick]

I'm with RD on this one. Bump the horsepower a few notches to see how you like it. Go easy on the alpha and you shouldn't have any problems. If in time you blow the Alpha, then go with the bravo. I can't imagine it would be worth the effort or $$. Unless you go with some serious horsepower, you're not going to get much better than 60mph out of jet. I know, I've got one.

[RiverToysJas]

I agree with the above suggestions of making what you have better. The money would be much better spent on a bigger motor and maybe a rebuild Bravo. You'll end up with a better boat for less money. Faster on top too.
RTJas http://free.***boat.net/ubb/biggrin.gif

[RiverDave2]

Ya know, I've never heard someone say that they wanted to go faster, then investigate the possiblillity of going from a prop to a jet in the same paragraph.. Interesting dynamic. This should be a "fun" topic. http://free.***boat.net/ubb/wink.gif
RD

[spectras only]

Maybe tooslow is not telling the truth about tired of trolling for rocks with his SD [rings the bell RD http://free.***boat.net/ubb/wink.gif ]and being an ex jetdrive guy ,he wants his freedom back, to roam around shallow waters and the odd rocks.BB / Jet = SB / SD in speed ,unless he really wants to go fast,go BB and SD. He already knows it's cheaper to maintain a jet,even with the extra cost of fuel with a BB http://free.***boat.net/ubb/wink.gif.

[SPECTRABRENT]

I would not convert your I/O to a jet. I/O's are worth more money. SEll your current boat and buy a jet boat. I have a friend that did this with a 20 foot Carrera and got WORKED.
Brent

[old rigger]

Horsepower is certainly one answer, but you guys are putting the cart before the horse, in my lowly opinion.
Tooslow, you gotta figure out where the X dimension is on your boat. If you are going to go to all the trouble of pulling the outdrive and filling the hole to make a jet out of it, why not fill the hole and re-rig it as an outdrive with the X moved up. I had the holes filled in my Spectra jet, and it cost about 600 bucks. Every boat's X is going to be different. And every customer want's something different out of his new boat. So the boat, in a custom shop, will be rigged acordingly. Maybe your boat new, was set up a little conservatly? I have no idea what the best X is for your hull, but it would be worth the effort to find out where it is now and go from there. Find some other of those older Ultras and check them against yours.
Pumping in more hoursepower, as you've found out, isn't always the soultion to going faster. There's free mph's (well not free if you have to have some glass work done) by just setting up the existing equipment the right way.
I also agree with fat rat, it would make much more sense to sell the thing and buy a boat that's already set up as a jet, if that's what you really want. That Spectra I have, I picked up as a bare hull on a trailer. I was lookiing for a boat to build a v-drive out of and it fit the bill perfectly. And it was cheap.

[wsm9808]

Unless you are into masochism, I would think about selling you boat and buying one that is already a jet. A conversion like that is one of those projects that a lot more of get started than ever get finished, and the expense would get way over the value of the boat. If you love long, chalanging projects you may enjoy doing it just for the satisfaction of knowing you did it, But I think its more than most people would want to get into. .02