SeaDoo SPI experimentation

[superiormarine]

I've got a '94 SPI that I am stripping bare to rebuild. Will be doing a lot of body modification (topside for looks only) and primo paint. The ol 587 is on her last legs and was thinking instead of a rebuild I'd see about getting a bigger powerplant. Has anyone tried to cram a 657, 717, ect in an SPI? I'd rather not rebuild the shaft seals or drive housing but moving engine mounts and possibly having widen the interior cavity would not be a problem. Of course I'd rather do all the glass work before painting . . . Main problem I see sould be the longer exhaust run but I may have an idea for that.

Before anyone replies with a "why bother", to me the SPI is like a bmx bike compared to motocross. May not be as fast but its small and light enough to respond like an extension of the body. Figured I'd give it a facelift.

Any help would be greatly appreciated.

Thanks, Lucas

 

[seadoosnipe]

Projects.....?

Welcome to the forum Lucas...........

So your looking to do a re-fit. "Why bother".........for me, the answer would be, "cause I want to!".......:rofl:

I don't think anyone can give you a lot of help. When you go to this modification, you'll be bringing in all the electronics. Nothing from the older motor will work.

As for the ski? I think it would hold up to a 717, by weight anyway.

Good luck!......let us know how it turns out.:cheers:

 

[kustomkarl]

This project will keep you busy for a while...Keep us all posted on your progress. Post some pictures now and then too.

Karl

 

[superiormarine]

caught in a quandry

Thanks for the quick replies. As you know, I would have to supply the electronics of course, and the quandry I'm caught in would be the interior size. In reality I should get the engine, hardware, and electrical first, then 'make it fit', then finish and paint. I just dont want to shell out for pieces parts only to find that I need to redo the entire pump and driveline. I'm reasonably confident that I can exchange couplers and slide 'em together but I'm concerned about the clearance on the exhaust manifold approaching the sidewalls and underneath the seat. I can widen the body cavity no problem but I'd rather not have to customize the seat as well. Unfortunately I passed on a great deal on a beat up xp that I could have used for reference (possibly even just swapped the engines). All of the regular schematics do not show dimensions so they have been of little help. From previous jobs I am aware that many of these era ski's use the same parts (different part numbers and prices but exact same parts none the less!)

Thanks again for the imput and I will certainly be posting pics and follow ups.

Lucas

 

[sporsterjoel]

unless your hearts stuck on a 94 SPI. id buy an xpl more power and better hull, just my 2 cents:cheers:

 

[seadoosnipe]

Weight ratio....

Have you checked on the weight of the newer motor. I dont' think it would be by much but the weight ratio to hull flotation my ply a role in your mod also.

The pump is probably going to be the same. The driveline hardware may be different. The older skis (pre 96) did not use the DESS system, so you only need to make sure you have a CDI or a DC-CDI system with all the compatible equipment.:cheers:

 

[Dennis]

engine swap

Use a 717 engine, exhaust and electrical system. It will fit with very little problems.
DAWG

 

[superiormarine]

used 717?

Thanks for the info dennis. May I inquire as to your confidence that the 717 will retrofit so well? Also, I'm going to look into buying a broken down ski with that motor, any suggestions? I think the older xp's had the white 717 if I remember correctly. What other ski's had the same? I figure I might as well just pick up an old ski to ensure I'm getting the whole system.

Also, one thing I prefer on the SPI is the spoon-type bow. I've never rode another ski that could do a REAL 360 on the nose at 20+ mph and continue on the same course, still planing. The short, reduced strakes and lack of chines of the SPI make it very slippery in a light chop, or what I call, a HECK of a lot of fun.

Thanks again everyone,
Lucas

 

[Dennis]

Hulls

Hi Lucas,
All 1994, 95 and 96 two seater hulls (SP, SPI, SPX, XP) are the same hull.
1997 SP, SPX 1998 SPX 1999 SPX are also the same hull as yours.
95 XP, 96 SPX, 97 SP had 717 engines. I would try to find a two seat donor ski because they will have other things your gonna need like throttle cable, etc. A three seat donor ski with a 717 will have different throttle, choke cables and possibly exhaust.
The hull type you have is considered, by most, to be most fun hull there is.
Good Luck, DAWG

 

[EvilVtec]

I agree with Dennis. The 717 is the largest of the "upright" engines there are. The 787 and 951 are mounted at an angle in the ski, which makes fitting inside the hull very tight. The power-to-weight ratio will be perfect. You need to find either a 95 XP or a 96 SPX donor hull to get all of your parts from, so that your fitment of exhaust components and engine mounts will go smoothly. Good luck with the work. And as far as the hull goes, you cant get any better than the X-4. I have a 717 powered 96 SPX with a pipe and oversized carbs, and in my opinion, there isn't anything else more fun!!!

 

[seadoosnipe]

hmmmmmmmm?

Good post you guys. I've known DAWG for quite a while so if he says it can be done, I believe him.

EvilVtec's in agreement with DAWG and makes a lot of good sense. I haven't known him as long but with these two mechanics to help you out, I bet you'll be flying in a new motor soon............:cheers:

 

[Stunnerable]

the hulls

Hey.. I love what your doing with the SPi. I feel old saying this but I loved the colors of the mid 90s Sea-Doos. Purple and Pink ROCK! Anyway, I wanted to clear up some info about the hulls in the SP-XP Sea-Doo skis.

X1 - The original series of hulls through 1993 on 2 seater watercraft. The 93 XP was the exception using an all new hull.

X2 - The hull used on the 1993 XP. This was the worst hull Sea-Doo ever made and in fact in the early 1994 model year Sea-Doo offered a kit free of charge (for a short time) to 93 XP owners. It consisted of GTX style sponsons to be mounted to the hull to increase stability and turning ability.

X3 - The hull that replaced the short lived X2. Used for the 1994-1998 SP, SPi, 1994-1995 SPX and 1994 XP.

X4 - Developed in a joint venture between Bombardier and Bullit Marine to create the perfect closed course racing hull for Sea-Doo's current 2 seater platform. It rode deeper with added strakes and a 3 piece "tunable" ride plate. Designed specifically for the 787 Rotax, however they used it on the 1995 XP (718). The X4 hull is found on the 1995 XP, XP800; 1996 XP; 1996-1999 SPX. Still the king of g-force in runabout class racing. Nothing in it's class even to this day can turn harder. Sport class and standup are the exceptions.

Good day.

 

[EvilVtec]

Just another testimonial to the X-4 hull. It may not be as fast stock as those new super-charged big boys, but the agility can't be replaced. Anything of the project yet?

 

[Bills86e]

Lukas, The 720 is the easiest and best choice. I think your electronics would
work as well, provided you use the stator and flywheel. The taper on those engines
ARE the same, but I recommend you blue it and lap it in. Nothing else is interchangable, so if it still runs, sell it for cash and find the 720. Alot are out
there complete with carbs & exhaust. I would look for the single carb engine as
it produces almost the same as duals, then your old cables might work. SO, you
would have to sell the 720 stator & flywheel, OR you would need an MPEM that
operates your skis hardware (tach,speedo,oil/fuel...whatever the spi has). 720's
don't utilize the pissers, so you'd need to make a plastic 3/8 tee - 1/4" to one
of the pissers, to the under exhaust drain line so you'd know the engine is cooling.
Get the short muffler. Your old belly plate should work to bolt in the 720. I also
recommend you re-align the engine with shims useing a special alignment tool. Its
easy, since you have removed the old pump to make way for a new one (you have
an old school aluminum prop) The tool bolts where your pump bolts, and you slide
the tool's Shaft in and shim until it glides PERFECTLY into the pto. You can use a big crowbar with a carpenters crowbar to break the old pump loose from the silicone
on/at hull. Remove the ride plate and re-glue to hull with The Right Stuff from the
auto part store, to prevent future cavitation (air). Clean the empty engine compartment good (mine was oily nasty, so I used gas, then diluted alot with water,
then sucked out all the crap with wet'n'dry vacuum). change out the fuel lines as
that modle used tempo gray (horrible) gas line. Use www.fuellineguy.com clear
racing gas line (20') and zip tie on. remove gas tank and clean it out. The bafel
has a circuit board that reads a float, and sometimes the pounding these machines
take, the bottom falls (and float) to tank bottom. Have fun with your project!

 

[timmyboy76]

Lukas, The 720 is the easiest and best choice. I think your electronics would
work as well, provided you use the stator and flywheel. The taper on those engines
ARE the same, but I recommend you blue it and lap it in. Nothing else is interchangable, so if it still runs, sell it for cash and find the 720. Alot are out
there complete with carbs & exhaust. I would look for the single carb engine as
it produces almost the same as duals, then your old cables might work. SO, you
would have to sell the 720 stator & flywheel, OR you would need an MPEM that
operates your skis hardware (tach,speedo,oil/fuel...whatever the spi has). 720's
don't utilize the pissers, so you'd need to make a plastic 3/8 tee - 1/4" to one
of the pissers, to the under exhaust drain line so you'd know the engine is cooling.
Get the short muffler. Your old belly plate should work to bolt in the 720. I also
recommend you re-align the engine with shims useing a special alignment tool. Its
easy, since you have removed the old pump to make way for a new one (you have
an old school aluminum prop) The tool bolts where your pump bolts, and you slide
the tool's Shaft in and shim until it glides PERFECTLY into the pto. You can use a big crowbar with a carpenters crowbar to break the old pump loose from the silicone
on/at hull. Remove the ride plate and re-glue to hull with The Right Stuff from the
auto part store, to prevent future cavitation (air). Clean the empty engine compartment good (mine was oily nasty, so I used gas, then diluted alot with water,
then sucked out all the crap with wet'n'dry vacuum). change out the fuel lines as
that modle used tempo gray (horrible) gas line. Use www.fuellineguy.com clear
racing gas line (20') and zip tie on. remove gas tank and clean it out. The bafel
has a circuit board that reads a float, and sometimes the pounding these machines
take, the bottom falls (and float) to tank bottom. Have fun with your project!

guy hasnt posted since, January...think the project was a success.