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1984 Johnson 15 HP

Discussion in 'Boats and Motors' started by CamdenGizzard, Sep 18, 2008.

  1. CamdenGizzard

    CamdenGizzard Elroderator

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    OK Here it goes.

    I'm crusin down the lake full throttle and she cut out. I can save it some times by choking it other times when I choke it it just continues to die. It never seems to happen until after the motor warms up. After it dies I'm able to start it right back up and take off. Then once I reach full throttle it does it again. Some times however it doesn't mess up it just cruses along like nothings wrong.

    Here is what I have done trying to fix the problem.

    1. Installed a fuel pump. (made no difference)
    2. Installed the rebuild kit for my carb (made no difference)
    2. Checked the gas (made no difference)

    Things I have noticed
    1. The primer ball stays rock hard.
    2. It seems less likely to mess up if I do not go FULL full throttle
    2. It only seems to do it once its heated up.

    Please any help would be so appreciated.
     
  2. Is it spitting water? It might be overheating Also check your gas lines. It sounds like it might not be getting fuel to run full throttle.
     

  3. CamdenGizzard

    CamdenGizzard Elroderator

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    Tale tail is flowing freely and stedily. As far as the gas flow thing goes. How would the primer ball be firm if it was lacking gas?
     
  4. UFM82

    UFM82 The one others want to be

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    Does it quit slowly like "cough, sputter, sputter, cough, die" or does it shut off like you turned the key? If the first, it's fuel. If the second, it's electrical.

    When you "installed" the carb kit, what did you do? Did you thoroughly clean the carb including every jet and passageway or did you just put the needle and seat in the thing and replace the bowl and body gasket? If the engine dies at full throttle like it's running out of fuel, I'd say it has dirt in the carb clogging a port at high draw. WOT on an outboard opens the butterfly completely and draws maximum fuel from the carb. This will suck any dirt up and stick it in a jet until the draw goes away. A 15hp engine should be simple to access the bowl on- I'd pull it and look for dirt laying in the bottom.

    If it dies instantly, (and you said you can save it by choking it at times), I'd say a coil is heating up, breaking continuity and dropping spark. Especially on a 24 year old engine. But reading your description that doesn't seem to be your issue.

    Fuel bulbs only go flat if you lose fuel between that and the tank. Collapsed line, no tank vent or clogged pickup will cause a soft or flat bulb. You've already replaced the fuel pump so that eliminates that. That leaves the carb.

    UFM82
     
  5. CamdenGizzard

    CamdenGizzard Elroderator

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    "cough, sputter, sputter, cough, die" for sure. I also only "feel" as if I cleaned the carb well. I didn't take it all the way apart. I guess I should do that. I'm gonna try my neighbors fuel tank and line first.

    If the coil were heating up it would continue to act up until the engine cooled, correct?

    Thanks for the wonderful description. It's one of the best i have received!
     
  6. UFM82

    UFM82 The one others want to be

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    I didn't put the southshore link in my reply. That's weird.

    And if you feel as though you cleaned it but aren't sure, ask yourself this. Did you get a can of carb cleaner and use the tube and spray it through every port, hole, passageway or galley in the thing? If you simply hosed off the outside and sprayed the throat of the carb, you misssed were the dirt is. It's inside the carb and disassembling it totally is the ONLY way to get it out. If your engine is close to what my 15 was (and most truly aren't much different), it should be a simple matter to take it apart and go through it again.

    And a coil, once hot, will cause issues until it fully cools in my experience. I actually don't run into nearly as many electrical issues as I do fuel issues. However, coils can be a pain. Usually they die and "poof", the engine quits and never starts again. However, sometimes...

    UFM82