Update on 70 Hp johnson rebuild

Discussion in 'LOCAL TENNESSEE TALK' started by TennesseeJugger, Dec 19, 2009.

  1. TennesseeJugger

    TennesseeJugger New Member

    Messages:
    2,029
    State:
    Watertown, Tenn
    Finally got the power head off today, got to the point of removing the cylinder head and water started to come out of the bottom cyl. Yep you guest it blowed head gasket. I will add more later got to get back out to it.
     
  2. biga

    biga Well-Known Member

    Messages:
    2,112
    State:
    evansville
    it was probably some water draining out of the waterjackets no nesissarily out of the cylinder.. 9 times out of 10 if you had water in the cylinder you would have known before you pulled it apart...
     

  3. TennesseeJugger

    TennesseeJugger New Member

    Messages:
    2,029
    State:
    Watertown, Tenn
    The gasket was blown.and there was rust colored water on the cylinder wall.
     
  4. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    Check the cylinder walls and see if they are out any to bad if not re ring it and crosshatch the walls and other nesseceary work and put her back to gether.
     
    Last edited: Dec 19, 2009
  5. TennesseeJugger

    TennesseeJugger New Member

    Messages:
    2,029
    State:
    Watertown, Tenn
    Found some minor scoring, so going to hone, replace rings and slap it all back together. This is the first time that I have ever done anything like this and I am kind of proud of my self. Thanks to all that provided info.
     
  6. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    Get mr hagen, I think that is the fellow s name thats helping you to show you how to check the head for flatness. Get a thread chasher and run all the block threads and clean all the bolt threads. Make sure you buy a top notch gasket to go back with. With the help you got it will be done right. If I ain't mistaken he is the same fella I bought an older 9.5 off of a few years back.
     
  7. AwShucks

    AwShucks New Member

    Messages:
    4,532
    State:
    Guthrie, Oklaho
    I used a 1/4 inch thick piece of plate glass to true my heads. Verify the surface with a metal yardstick. Glue pieces of emory cloth onto the glass. Start rubbing the head across the emory cloth in a figure 8 pattern. The areas which have been trued show as a shinny surface. Keep doing this until you have a completly shinny surface in the area which meets the cylinder walls. I used this method for a 50 HP Evenrude and both heads from a 70 HP Evenrude. Works grea.