Super Jet SN 701 Swap - No Power

[STi410]

Hey guys, I am new to the pwc scene and am a bit stumped with this problem I am having with my superjet, hopefully you guys can give me some ideas.

I just got a 93 650 superjet, it started and ran well, but didnt seem to have much power in the water so I pulled the carb apart and cleaned it. Didn't change anything. I bought a brand new carb and installed it, still no change. After some research found out the 650 really isn't worth putting money into, so I bought a 95 raider and swapped in the 62t/62t. I used all the radier components including electronics, but used the stock 650 exhaust and just ported the exhaust manifold to match the cylinder ports. To my dismay it didn't change anything! Its a little faster but not by much.

I am tired of pouring money into this thing and want to make sure the next thing I do fixes it! Its got to be something I haven't changed, basically the pump or exhaust.




The impeller has some nicks in the leading edge, and the wear ring is a little worn. It has definitely been used, but it doesn't seem bad enough for it to not hook up at all. The gap is approx .025" all the way around.

The midshaft seal looks visually ok, and if you hold the back of the ski underwater it doesn't leak, but thats not to say it doesnt pull air through when its running.

What is my best chance of solving this?

Thanks for the help!

 

[550headache]

that prop is FUBAR!

what jetting are you running? maybe that's off. slap a AM pipe on there. stock pipes are basically mufflers. everyone loves the factory b pipe but its a lot of $$! I found a used pro tec for $250 and it transformed my 701 in my fx1!! just saw one in the parts for sale section on this site for a good price

 

[iangdesign]

That prop is eaten up buddy!

You should see some gain in power from a 650/701 swap, but agree your exhaust is limiting as well. There are a ton of things you can do to improve the ski, but it all costs $$$$. This ain't a cheap hobby/sport.

 

[stagesrt4]

impeller is pretty much toast


could you tell if the lack of power was motor or drivetrain related??

 

[STi410]

Alright so I have a pro-tec pipe coming, along with a high compression head. I could not tell if it was a lack of power or a drivetrain issue. The motor did seem to rev faster than the ski accelerated, and everyone is saying the impeller is toast so I think the next step is impeller. I found a decent deal on a new skat trak 15/20 swirl. Will this perform well for a freeride/mess around ski?

 

[stagesrt4]

yeah most signs are pointing to impeller

that impeller shot!..... way too much wear on outter edge of blades n those are some big chunks in blades

 

[STi410]

Alright new impeller/wear ring it is. Wish I would have known those dings would make that much of a difference before I swapped engines... :frown:

 

[Captain PegLeg]

With that engine, pipe, and a new prop you shoud have a significant improvement given you tune the carb right! best of luck!

 

[OCD Solutions]

You haven't wasted a penny yet in my opinion. You won't regret any of the mods you have done so far and a new impeller should smarten that right up.

I picked up a GP800 a few years back that was an absolute dog. The impeller was worn a little worse than yours. The thing would rev to 8000 rpm and only be doing like 35 mph. I dropped in another stock impeller and the difference was night and day. I never would have believed the clearance played that much of a role if it hadn't been for that experience.

I still wouldn't rule out something else like a plugged water box either. Been hearing that one a lot lately although I have never experienced it myself.

 

[STi410]

That is encouraging! I ordered a hooker 9/15 a week ago but haven't heard anything back from impros, hopefully they shipped it but I doubt it. New wear ring will be here today. I pulled the waterbox and it was unobstructed as far as I could tell. Once I get it all together I will report back. Thanks guys.