SBT Jetski Engines, Parts & Accessories

Results 1 to 4 of 4
  1. #1
    Joined
    Sep 2005
    From
    Raleigh, NC
    Posts
    6

    Red face Seadoo Rotary Valve damage - Advice needed

    Hi Folks,
    I'm helping a friend fix his 1990 Seadoo SP. I've found the problem that was causing a binding and clicking (popping) noise when the crankshaft was manually rotated clockwise.

    My question will be whether the damaged crankcase can be reused. Can they be resurfaced? I know the rotary valve clearances are very important, so I
    have my doubts. Definitely need a new rotary valve.
    Several photos of the damage can be viewed here -
    http://home.earthlink.net/~powerski/SeadooSP

    The obvious problem (now that I can see the rotary valve) is that the
    leading edge of the rotary valve shutter is damaged, and whatever foreign
    object it hit, got dragged around underneath the rotating disk and has badly
    scratched the mating surface of the crankcase. I'd estimate the the 4"
    diameter circular gouge is at least 1 mm deep and the right intake port has
    a 2mm notch taken out of the upper side. A chunk of metal the size of a
    metal thumb tack head which appears to be part of the foreign object that
    caused the damage fell out from behind the rotary cover when I removed it.
    It looks like the foreign object got scissored against the right intake port
    edge by the spinning rotary valve.

    Now that the rotary valve is removed, the engine turns freely and I can not
    feel any broken teeth when the rotary shaft turns. So I'm trying to work
    out where the foreign object came from. Next, I will be pulling the rotary
    shaft for inspection. The popping noise during rotation is no longer there,
    so the rotary shaft may be fine.

    Thank you for any advice on this.

    Regards,
    Jono

  2. #2
    Joined
    Feb 2004
    From
    New Jersey
    Posts
    2,601

    Default Re: Seadoo Rotary Valve damage - Advice needed

    the case is shot , it can be fixed but it would be cheeper to go shopping on ebay for a case that is clean , or buy a SBT shortblock and have a warranty i would bet when you split the case you will find the rotory gear is damaged and shaft is bent
    PRIDE IN SERVICE<br /> <img src="http://www.sbtontheweb.com/images/forposts/4609/1.jpg" alt=" - " />

  3. #3
    Joined
    Nov 2003
    From
    Glendora, CA
    Posts
    6,846

    Default Re: Seadoo Rotary Valve damage - Advice needed

    Somebody just installed new pistons and they left something inside of the motor??
    Bill O'Neal <br>
    WCM
    <a href="http://www.watercraftmagic.com"

  4. #4
    Joined
    Sep 2005
    From
    Raleigh, NC
    Posts
    6

    Default Re: Seadoo Rotary Valve damage - Advice needed

    Yes, it seems so. I've got to give him some credit though. It was this gent's first time rebuilding an engine. No mentor, just a Clymer manual. I imagine lots of unfamiliar territory, a little scary, but at the same time the glimmer of excitement with thoughts of getting back out on the water.

    Regards,
    Jono

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. 95 Seadoo SPX Rotary Valve Seal
    By jbissn in forum Sea-Doo
    Replies: 3
    Last Post: 08-09-2006, 04:41 PM
  2. seadoo 787 rotary valve engine
    By twttom in forum Sea-Doo
    Replies: 1
    Last Post: 06-26-2006, 09:18 AM
  3. Rotary Valve cover - damage or normal?
    By seasoned in forum Sea-Doo
    Replies: 5
    Last Post: 12-02-2002, 01:03 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •