Register

If this is your first visit, please click the Sign Up now button to begin the process of creating your account so you can begin posting on our forums! The Sign Up process will only take up about a minute of two of your time.

Results 1 to 4 of 4

  1. #1

    Join Date
    Jun 2007
    Location
    buttonwillow, CA
    Posts
    93
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    OPS 90 tuning help needed

    I have a used OPS 90 that I had to put a new piston /sleeve into. I just started it for the first time and it starts right up but then wants to kick over and run backwards. Causes/ solutions for this? I have 30% fuel in it for now and a medium heat glow plug. If the timing in the motor has been changed I am not aware of it.

  2. #2
    piper_chuck's Avatar
    Join Date
    Jun 2004
    Location
    Columbia, SC
    Posts
    8,039
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    RE: OPS 90 tuning help needed

    Are you using 12 or 24 volts to start it? If 12, consider switching to 24. On the big block engines, 12 volts aren't enough to overcome the compression, especially with a new piston/liner, and turn the engine at a good starting speed.
    AMA 87959

  3. #3

    Join Date
    Feb 2007
    Location
    Newcastle, UNITED KINGDOM
    Posts
    1,385
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    RE: OPS 90 tuning help needed

    As above plus:

    Is the backplate and disc back in the same place it came from?

    Also, have you altered head shims at all to alter compression?

    Glenn

  4. #4

    Join Date
    Jun 2007
    Location
    buttonwillow, CA
    Posts
    93
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    RE: OPS 90 tuning help needed

    I do have the 24 volt starter and it turns it well. It will start and run the proper direction for a few seconds and then stumble and reverse on its own. My disc opening begins to appear about 1/8" after the piston passes bottom dead center. I think this is correct? I reassembled using the head shims it came with(used). I am not sure about the thickness/number of the original head shims.


Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
All times are GMT -6. The time now is 03:15 PM.

SEO by vBSEO 3.6.1 ©2011, Crawlability, Inc.