120 johnson

Discussion in 'Bubba's Outboards' started by maddkatz22, Jul 29, 2007.

  1. maddkatz22

    maddkatz22 New Member

    Messages:
    45
    State:
    South Carolina
    I have a 1991 Johnson 120 (BB or 90 degree) that has a broken ring in the # 1 cylinder. It has scared the head and a small scare in the cylinder wall. All of the other cylinders test at 120psi. My question is should i just rebuild that one cylinder or replace the motor or rebuild the whole motor? Any help would be greatly appreciated. Thanks
     
  2. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    You can get away with rebuilding Just one cylinder. I have rebuilt one cylinder and got many hours of service out of them . I would take it to a shop and have it bored and replace that one cylinder piston and add new bearings through out and hone the other cylinders and new gasket set.

    You need to find out what caused this failure and fix that problem right along with the repair. I suspect coking is what caused it. You can opt to buy another motor but you buy used you still don't know what you are getting and if you opt to repair and do most of the work yourself then you know what will be hanging off the transom and most likely will stay in the price range of a used motor of that size and year.

    If it were mine I would rebuild.
     

  3. maddkatz22

    maddkatz22 New Member

    Messages:
    45
    State:
    South Carolina
    Bubbakat,would you bore that one cylinder to a bigger size than the other pistons or what? Sorry for the stupid questions?
     
  4. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    Yes they will bore it over size and if it doesn't go to far you can install an over size piston if it has to be bigger then the shop will sleeve it back to the original size.
    And ain't no question stupid. With me I take it for granted sometimes that most people share the same knowledge that I do on outboards and can get a little sketchy with my explanations sometimes