Results 1 to 5 of 5
  1. #1

    superjet piston only moves halfway.

    Hey guys, i new to forums so forgive me if i do something wrong. i recently bought a 1992 yamaha superjet and its been giving me some troubles. I just put a new battery in it and when i hit the start button i heard the starter engage but the motor didnt turn over . so i decided to pull the plugs to see if it would turn over and it didnt. This ski has been sitting for about 10 years so i assumed something would go wrong. i started trying to turn the engine over by hand and it worked for about a full turn however only one of the pistons moved. i hit the start button again and they both cranked once really quickly but now one seems to be stuck at the bottom of the cylinder, it will go up halfway nut then gets stuck again. how can i get it unstuck? any help is appreciated.


  2. #2
    800AMSOIL4U's Avatar
    Join Date
    Aug 2006
    Location
    Morgan Hill, CA
    Posts
    5,025
    +1
    133
    Sounds like a broken rod.

  3. #3
    Banned User
    Join Date
    Sep 2014
    Posts
    1,150
    +1
    132
    Blown engine (broken rod or crankshaft).

    Hope you didn't pay much that's about a $1000 repair.

  4. #4
    Prism's Avatar
    Join Date
    May 2007
    Location
    "New" Jersey
    Posts
    826
    +1
    100
    If the pistons only move halfway like the title says, I would make sure the impeller isn't binding on the pump wear ring. If it's free, then I would agree with what has already been said....broken rod or crank. Pull the pump back and try it.
    Last edited by Prism; 05-23-2015 at 08:12 AM.

  5. #5
    As has been stated. If one piston moves when the engine is cranked and the other piston does not, then definitely broken/damaged internal components.

    Which piston is not moving? Is it the rear?

    Fortunately, that's an easy motor to work on.

Thread Information

Users Browsing this Thread

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

Similar Threads

  1. 2004 Genesis Ficht engine burn down CEN piston only
    By K447 in forum Polaris Open Discussion
    Replies: 0
    Last Post: 09-07-2013, 01:18 PM
  2. Replies: 15
    Last Post: 07-02-2013, 10:35 AM
  3. Replies: 4
    Last Post: 08-30-2011, 11:02 AM
  4. WTB riva 20 over piston only 1
    By rxpredviper in forum Sea Doo Classifieds
    Replies: 3
    Last Post: 04-23-2010, 07:00 PM
  5. 1997 Seadoo challenger only moving 15mph
    By synergy141 in forum Sea Doo Sport Boats
    Replies: 2
    Last Post: 07-24-2009, 11:07 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
  •