1977 70 hp johnson

Discussion in 'Bubba's Outboards' started by aaron, Sep 17, 2007.

  1. aaron

    aaron New Member

    Messages:
    21
    State:
    louisiana
    70 hp johnson and i have no fire!

    we just got the boat from a guy at work he said it ran last year
    i know him and have no reason to doubt him any ideas on what could be wrong
    thanks
    aaron
     
  2. AwShucks

    AwShucks New Member

    Messages:
    4,532
    State:
    Guthrie, Oklaho
    It sure gets frustrating at times trying to trouble shoot these motors. So far I have had to get a compression gauge, an electronic spark tester, two manual spark testers, had to buy a new power pack because mine wouldn't fire, new stator and rectifier to rebuild the motors charging system, rebuilt lower unit and through all that I am as happy as a turtle on a log.

    My first pearl of wisdom is... if you haven't all ready done it, get a manual which covers your motor. Besides trouble shooting problems as this, they also have all the instruction for linkage settings, for the sync and link procedures (timing), test on all kinds of components on the motor.. you really need a manual.

    In addition to the year, bubbakat will probably need the model number also. These things are like fords and Chevy's ... they are both cars but a mile apart in the maintenance and performance.
     

  3. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    The first thing to do when an outboard won't start is do as larwrence suggested. Buy or borrow a manuel to trouble shoot those things. It will prove to be invaluable in the long haul. You can either buy one or go to your local library to check one out.

    The one thing that most engines have in common is a kill switch. You can take the big plug that hooks all the wires up to the motor and it is located on the motor at the bottom of the power head inside the pan. Take it apart and then short the selnoid out from the hot post to the little stud and try to start. This will elimenate the kill switch. Or go to the engine teminal blck and find the black with yellow stripe wire and disconnect that and that will take the kill switch off line.
    If it does start then you will have to choke it down with the choke. If it does start then the switch is most likely at fault.
    When you say won't start does it spin over but doesn't fire up. or just nothing at all.
     
  4. aaron

    aaron New Member

    Messages:
    21
    State:
    louisiana
    we ordered the book this week it should be in soon

    the engine will turn over fine just no fire
    i will try to disconnect the blk/yel wire and start it this weekend
    thanks
    aaron
     
  5. SUNDROP

    SUNDROP New Member

    Messages:
    395
    State:
    Washington
    magneto trigger on the flywheel may be corroded. You need a manual for sure! I have a 75 70hp Rude and it has been valuable to me. I bought an original factory repair manual on Ebay for $6. I'll see what it says about your situation and get back to you..