Compression

Discussion in 'Bubba's Outboards' started by droptine77, Jul 18, 2007.

  1. droptine77

    droptine77 New Member

    Messages:
    469
    State:
    Anderson, SC
    I have a 83 90hp Evinrude and was wondering what the compression should be for its age. It has 119, 119, 118.5 and 118.5psi if lookingfrom left top to bottom. Any help would be appreciated.
     
  2. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    There is nothing wrong with that compression Greg you might do a good decarb and bring it up some but all the cylinders are well within the 10% range and should work fine.
     

  3. droptine77

    droptine77 New Member

    Messages:
    469
    State:
    Anderson, SC
    What is a decarb? I'm not the greatest at outboards.
     
  4. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    Take a can of sea foam or power tune. I use sea foam myself. Get you a gallon of fresh fuel. Mix about 2/3rds of the can with the fuel. Hook the motor on the muffs and hook the tank with the gal of fuel mix in it. Oh BTW be sure to add the oil to the gal also. Let the engine idle for about 10 min on the muffs to warm up. Now keep in mind its going to smoke a Lot and don't stand where the exhaust will hit you are anything that you don't want to get dirty.
    After it warms up shut it down and lean the motor in the transport position and take the plugs out and Pour the remaining sea foam (uncut) in each spark plug hole.
    Let it set for a couple hours No set time on the soaking I have left them for up to 10 hrs. Take it to the closest ramp where you can put it in the water and run it at wot.
    Warm it up at the dock and run it like you stole it. This will clean all the coking out of the cylinders around the rings Which in turn make your engine run better
    After doing all this if the plugs are less then a year old clean them real good and re gap if they are a year old replace them.
     
  5. shane12970

    shane12970 New Member

    Messages:
    131
    State:
    , North Carolin
    what is wot? thanks shane
     
  6. droptine77

    droptine77 New Member

    Messages:
    469
    State:
    Anderson, SC
    Shane it's Wide open throttle I believe. Thanks Willard for all your help!!