Page 1 of 3 1 2 3 LastLast
Results 1 to 10 of 21
  1. #1
    blegan's Avatar
    Join Date
    May 2008
    Location
    bakersfield
    Posts
    321

    paranoia or reality

    Im in the middle of a 94 slt 750 rebuild & yesterday I googled polaris 750 w/ hole in pto or mag piston & I was surprised at the number of people who made the repairs & still burnt another hole before they even got out of the no wake zone. I have completely rebuilt fuel sys. from tank pickups all the way back to rebuilt carbs.& fuel pump. There was about 6 individual problems in fuel sys. to cause a lean cond. Ive Indexed the crank & that is not a factor here, from what Ive been able to learn is that the one last factor would be leaking main seals. I dont want to waste the money Ive got wrapped up in this project & have to tear it down again & spend more good money. Ive been financially commited since about $6-700.00 ago! So to answer my own question I guess I play it safe & split the cases & replace crank seals.or I have the motor tore down to shortblock cyls. off,exhaust off,reeds & intake off. How do I perform a leak down at this point.
    Thanks Brian


  2. #2
    ryandi2's Avatar
    Join Date
    Aug 2009
    Location
    conesus ny!
    Posts
    2,092
    +1
    19
    im not sure if this test works for that or not but what about doing a leak test or pressure test? again i dont know its possable for main seals.. but maybe some on will chime in that knows about that stuff..


    i be you are fine though pretty much everything on your ski is new.. how do your carb too intake mani gaskets look?
    Last edited by ryandi2; 03-25-2010 at 10:03 AM. Reason: spelling

  3. #3
    Moderator beerdart's Avatar
    Join Date
    Aug 2006
    Location
    CT
    Posts
    25,930
    +1
    1,407
    Yes a leak test will show if the seals are leaking

  4. #4
    Hayabusa's Avatar
    Join Date
    Sep 2006
    Location
    Trenton Michigan
    Posts
    493
    You can certainly do a leak down test and you don't tear the engine down, to do it. Just do a search on it and you will get way more information then I can quickly write in this post. If it does leak, you can use some soapy water around the rear seal, cases, etc. to try and spot it.

    The crank seals do go bad so yes, it can cause a lean condition. The rear of the crank has 2 seals placed back to back. There is only one in the front.

  5. #5
    blegan's Avatar
    Join Date
    May 2008
    Location
    bakersfield
    Posts
    321
    Quote Originally Posted by Hayabusa View Post
    You can certainly do a leak down test and you don't tear the engine down, to do it. Just do a search on it and you will get way more information then I can quickly write in this post. If it does leak, you can use some soapy water around the rear seal, cases, etc. to try and spot it.

    The crank seals do go bad so yes, it can cause a lean condition. The rear of the crank has 2 seals placed back to back. There is only one in the front.
    Thank you, either Im retarted or I just dont understand search function!
    I completely understand that cases do not need to be split to perform leak down test, My question is what do I use or where can I get the material to use for blockoff . Not wanting to be another 750 fuji casualty,Thanks
    Brian

  6. #6
    Moderator beerdart's Avatar
    Join Date
    Aug 2006
    Location
    CT
    Posts
    25,930
    +1
    1,407

  7. #7
    blegan's Avatar
    Join Date
    May 2008
    Location
    bakersfield
    Posts
    321
    Quote Originally Posted by beerdart View Post
    What about tennis balls? Ive always got lots & lots duct tape! LOL
    Thanks for the link Sir.

  8. #8
    blegan's Avatar
    Join Date
    May 2008
    Location
    bakersfield
    Posts
    321
    I thought that was a joke, the raquetballs & duct tape! Jokes on me. Learn something new here everyday.

  9. #9
    Tony's Avatar
    Join Date
    May 2007
    Location
    North Carolina
    Posts
    1,760
    +1
    38
    Pull a vacuum. You'll need Plexiglas, RTV, and a hand pump.

    http://greenhulk.net/forums/showpost...1&postcount=13

    I let it sit for 24 hours and then applied some RTV around the intake and exhaust manifold and used Plexiglas to seal the openings. I used a mityvac hand held pump and applied 10" of vacuum and watched the clock. I started at 1:07 and at 1:21 I had only lost 1/2" inch of vacuum...not to shabby.

  10. #10
    Click avatar for tech links/info, donation request K447's Avatar
    Join Date
    Jul 2007
    Location
    near Toronto, Canada
    Posts
    36,595
    +1
    1,276
    Quote Originally Posted by Tony View Post
    Pull a vacuum...
    You can use vacuum to prove the engine is good, but vacuum is not so useful to find a leak.

    You need air pressure and soapy water to see the bubbles where it is leaking.

    With a vacuum, it will just draw the soapy water inside - not really what you want.

    When applying air pressure, you just need a few PSI

Page 1 of 3 1 2 3 LastLast

Thread Information

Users Browsing this Thread

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

Similar Threads

  1. Bow Rider or Open Bow
    By MikeTrin in forum Sea Doo Open Discussion
    Replies: 14
    Last Post: 05-26-2005, 02:28 PM
  2. hey Jerry, or Miketrin, or 11, or anyone who would know...
    By theantiRXP in forum Sea Doo Open Discussion
    Replies: 1
    Last Post: 05-23-2005, 08:56 PM
  3. 05 or 06 RXP ???
    By Wes901 in forum Sea Doo Open Discussion
    Replies: 11
    Last Post: 05-22-2005, 05:54 PM
  4. How did you modify your craft? all at once or 1 at a time?
    By theantiRXP in forum 4-Tec Performance
    Replies: 12
    Last Post: 05-14-2005, 05:44 AM
  5. PPG or Riva Air Intake, can't decide
    By Shibby1485 in forum 4-Tec Performance
    Replies: 11
    Last Post: 05-12-2005, 05:50 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
  •