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  1. #1

    Cool Advice Needed, 97 SLT780 low RPMs

    New SBT engine- block was cracked when I pulled the old engine to rebuild after rear piston blew

    Jet Pump rebuilt by PWC shop

    Carbs professionally rebuilt by PWC shop to factory settings

    New impeller installed- Solas X Prop 14/21 pitch (towing and high altitude prop)

    Starts easily and runs, just not getting the speed I used to in the water. Tops out at about 4200 RPM at WOT.

    I did all the checking to find out if it is in "limp home mode" and even disconnected the gray wire and no change in performance, so its not in limp home mode.

    What should I do next? Different CDI? Advice needed....nothing worse than having put all this money into the ski for it to perform like $%&#.

    Also, when I cracked open the CDI to disconnect the gray wire, I was going to go ahead and check the ohms for the stator and coils...the color wire combinations did not seem to line up with those given in the tech. guide. I don't have a pink/white wire, etc. 2nd owner since new...first owner is my best friend who didn't change anything out on it.

    Thanks in advance.


  2. #2
    She likes the bike. But the ski gets her wet!!!! xlint89's Avatar
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    Welcome to the Hulk.

    Sorry to say, but I'd be contacting the PWC shop you had do the work....

    Not sure what you read for a pink white wire, but there is none for a Fuji (blue) engine.

  3. #3
    Click avatar for tech links/info, donation request K447's Avatar
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    Quote Originally Posted by xlint89 View Post
    ...contacting the PWC shop you had do the work....
    That would be Dale's Jet Sports in Sachse, TX

    Something is not right with your engine (obviously). Could be ignition, carburetors, compression...

    Since the rebuild, did it ever run properly, even for a few minutes?

    Check cylinder compression. All spark plugs out, throttle held wide open.

    Oh yes, welcome to the Hulk

  4. #4
    It wasn't a rebuild, I put in a remanufactured engine.....and no, its never run quite right since the reman. Fuji was put in. Great compression on all 3 cylinders. New plugs, have trimmed the spark plug wires.

    Unfortunately current employment situation doesn't lend to paying a shop big $$ to track this down, that's why I'm here trying to figure it out myself. At this point I gotta get it going good so I can either ride it or sell it.

    As for the CDI, can't remember specifically which wire did not match up, but all my wires were different colors than those listed in the knowledge database for the Fuji engines listed here on The Hulk, even though it said a 97 780 was used for reference. The only colors I had that matched were the Red/Purple and Yellow. http://polarispwcknowledge.shorturl....ed-polaris-pwc I've even tried to find a PWC mechanic looking for side work on craigslist here in the DFW area, but no responses.

    Thanks for any further advice.

  5. #5
    TopCop931's Avatar
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    Can you get it above 4200 rpm's when the engine is not under load? It is a stretch, but if you can maybe the problem is located at the jet pump. The reason I am saying so is because I have been experimenting with impellers and found that some can really cause problems with rpms and drag. I tried out a new Solas impeller with the exact same pitch as you describe and got up to only about 5800 rpms on my 96 780. I threw my other pump back in and with a progressive impeller and ran fine again.

    Of course if you were using that impeller before the engine change that would not be your problem.

    The two most frequent and knowledgeable posters on here in my opinion, have already given advice. They both really know their stuff. Maybe more info and pics on those wires you're talking about will give them a better idea of where to look next.

    Did you check compression as K447 advised? You could have gotten shorted on the job as xlint suggested.

  6. #6
    She likes the bike. But the ski gets her wet!!!! xlint89's Avatar
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    How about a pic of the CDI in question please?

  7. #7
    I believe the X prop you have may be too much prop for your ski. Had an X prop in my brothers SL900, and took all that 2 seaters HP to move it. I Throw that in a lower HP 3 seater and I believe it's even tougher to move that prop. I'm not saying 4200 rpm, but right now going back to stock prop so you can get your rpms up and see how much rpm's you lose when you have it running right.

  8. #8

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    always go with the stock prop for tuning purposes

  9. #9
    Out of the water WOT will rev to 6600 rpm. Runs pretty smoothly in the water, just sluggish.

    Starting to think it was the prop that I let them talk me into putting in when they rebuilt the jet pump. There are several factory impellers on Ebay, I'll pick one up and try it out. Been a busy week getting the kids back into school, will get a pic of the CDI up sometime over the weekend. I greatly appreciate all the help.

  10. #10
    TopCop931's Avatar
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    Quote Originally Posted by robbpoe View Post
    Out of the water WOT will rev to 6600 rpm. Runs pretty smoothly in the water, just sluggish.

    Starting to think it was the prop that I let them talk me into putting in when they rebuilt the jet pump. There are several factory impellers on Ebay, I'll pick one up and try it out. Been a busy week getting the kids back into school, will get a pic of the CDI up sometime over the weekend. I greatly appreciate all the help.
    Damn. I just sold an impeller that could helped ya out. The 5131371 is the stock impeller for your ski. I saw a few that were in good shape on fleabay for about $80.00. Check the classifieds here also. I thought I saw a 780 part-out over there yesterday.

    You also may be sucking air in that pump. Like I said. I ran the Solas PA-SC-X prop in mine and got about 5800 rpms at 3/4 throttle which is about right. It just didn't feel right when I tried to push it wot. I ran an 035 and got a lot of thrust but felt there was too much on the motor at wot. I am now back to the 1371.

    Which "X" prop did you use? If it was the same one that I ran then I don't think that is the issue. The Solas prop that I have is also 14/21 and was made for these Polaris Skis:

    POLARIS:
    96-97 SL/SLT 780/785
    96-97 SL 900
    97 SL 1050
    99-04 GENESIS/I

    of course this is according to Solas.

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