Results 1 to 5 of 5

Thread: Blown Engine

  1. #1

    Blown Engine

    97 700 slt

    Well I had the Front rod bearings come apart on me this weekend after ten mins of riding. It trashed the engine. I had a fuel issue that I had been working on, dont know if it took its toll on the bearings or if they just failed. The ski would work perfect for the first hour of use then it started cutting out at at wide open throttle and would get worse as the gas level went down. Rebuilt the fuel pump and carbs, found the back accelerator pump injector clogged. This did not fix the problem. Filled tank and ran perfect for about the first hour again. Problem returned did some research on this site and found that the fuel system has to be completely sealed so it will build pressure and assist the fuel pump to supply fuel to the engine. Sure enough found the gas cap was missing a third of its gasket. while i had the carbs off I inspected the reeds and they all were off their seats. I polaris mech. told me it was ok to flip them over so they will seat. I did and they seem to seat ok. I took the ski out and within ten mins of warming the engine up on a half a tank of gas It cut out a few times and then ran good and strong for about 200 yards and then lost the bearings.
    I pulled the cylinders and the front needle bearings on the crank journal was the culprit. the back was fine. This destroyed the piston, rod, head, cylinder.

    Question: When I took the engine apart there was no water in the head, cylinders or exhaust or the hoses. So far I can not find anything clogged. I have yet to inspect the hole were the inlet is since I have to take off the jet pump. Should there be water in the system when I took it apart?

    Question: Running the ski for the last two weekends with the fuel problem (cutting out\ starving for fuel) caused it to fail or at least contributed the bearing failure?
    Last edited by crashem; 07-02-2007 at 01:49 PM.

  2. #2
    ph2ocraft's Avatar
    Join Date
    Apr 2006
    Campbell, Ca.
    How many hours were on the engine?
    Those crank seals, when bad, are good for a lean running condition.
    Or possibly just tons of hours on the engine??

  3. #3
    I just bought the ski from a friend's neighbor he took very good care of the ski. I called and he said it had between 40 and 50 hours on it.

  4. #4

  5. #5
    ph2ocraft's Avatar
    Join Date
    Apr 2006
    Campbell, Ca.
    Can we get a photo of the piston tops and plugs?

Thread Information

Users Browsing this Thread

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

Similar Threads

  1. What might be the cause of a blown engine?
    By Hecyan in forum 4-Tec Performance
    Replies: 9
    Last Post: 06-30-2008, 07:30 AM
  2. 04 GTX 4 TEC Blown Engine?
    By twinsx3 in forum 4-Tec Performance
    Replies: 5
    Last Post: 05-29-2008, 06:47 AM
  3. XL1200 & GP800 w/ Blown engines
    By wfhaynes in forum Yamaha Open Discussion
    Replies: 5
    Last Post: 04-27-2008, 08:07 PM
  4. Blown Engine, Rebuilding Now, Please help
    By havanabama in forum Yamaha How To & FAQs
    Replies: 2
    Last Post: 01-13-2008, 09:08 AM
  5. 03 gpr blown engine
    By MDGPR in forum Yamaha PWC Performance (2-stroke)
    Replies: 3
    Last Post: 06-12-2006, 10:16 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