need help with engine swap

[ben]

I have been having steady problems with the 650 in my 93xp so I am grafting in a 720. I already have the engine(it came from a 96spx) and I have the manuals and wiring diagrams. question 1 the stator in the 650 has five wires, and the stator in the 720 has four wires. So, do I just swap the stators, or is there another way that this has to be done?
2- does the MPEM have to be changed due to RPM or is it ok?
3- I didn't get any carbs with the engine, what do I do to the 650 carbs to make them work?
4- do I have to install a new impeller, and what will happen if I don't?
5- do I have to change the exhaust or will the 650 exhaust work for the 720?
Thanks in advance

 

[kustomkarl]

Good luck with the project. The info you need would take me all night to explain the differences between the 2 engines. It sounds like you need a shop manual for each engine to get it right. Here’s an idea for you. You could join as a "premium member". As a premium member you can down load a authentic seadoo manual from the seadoo manual library. In the library is a variety of manuals for almost all years and models. You can view as many as you like on line as a PDF file, or download it and print it for your personal and private use. There are operator manuals and repair manuals for you to do your own repairs on your seadoo. The repair manuals have everything from troubleshooting, repair procedures to winterizing. It contains wire diagrams torque specs and pictures for disassemble and assemble instructions. In the spec sheets it tells everything needed to maintain oil changes, spark plug gaps, carburetor rebuilds and impeller wear ring tolerances. Click on the "Seadoo Manuals" link at the top of the page for more details. If you need any help or get in a jam, we are always here to answer your questions too. Premium members get priority when it comes to getting quick detailed answers.


Karl

 

[ben]

I have the manuals for both machines(93, and 96). I can probably figure out most of the stuff through hard research, but I just hoped you could make it a bit easier for me.
ok just one question what do I do to the carbs to make them work in this application?

 

[Dennis]

engine swap

Hi BEN,
The 93 650 carbs will not work on a 720. The 720 carbs are bigger. Also, the throttle and choke cables on the 93 XP will not work on the 720 carbs. I can think of a few more things that will give you trouble. My advice is not to install the 720. It's gonna be a hell of a lot easier to replace your 93 XP engine with another twin carb 650 engine.
Good Luck, DAWG

 

[derek]

the carbs will work on the 720. not as well as 720 carbs, but they will run. use the 720 exhaust. the water runs backward through 720's compared to 650's. hits back of head, and goes out thru exhaust manifold into exhaust. 650 comes in thru exhaust, and enters engine thru exh manifold and leaves at the back of the head. some aftermarket head manufacturers make a 720 head that has to be watered the 650 way, so if all you have is the 650 exhaust, it would probably be ok. but i would recommend shopping for 720 exh. keep an eye on temp. use the stator that came with the ski and you won't have to do any re-wiring. check your timing. the marks on case and stator are probably accurate, but but you can't assume that. the mpem won't know the difference in engines. you don't have to change it. both skis timing spec is 19 to 21 degrees. impeller; there is very little difference. you will be ok for now. they are both 11 degrees on the outside edge. the 93 650 was 60 or 70 hp, depending on who you believe. the 720 is rated at 85 hp. you won't feel much difference.

 

[RX951]

He is correct. Not much of a power difference in stock form when comparing the 650-720.