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25hp Evinrude Problems

Discussion in 'Boats and Motors' started by feetdown, Jun 4, 2008.

  1. feetdown

    feetdown They call me "BIG POPPA"

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    I have a 1977 evinrude that will idle fine and run at low throttle without problems.. When I open it up it starts to miss severely.....I dont know where to start looking for problems..I changed the plugs and rebuilt the carb...I even tried a new fuel line. I cleaned the fuel filter and the screen....What should I look for ?...............Thanks
     
  2. Hetfieldinn

    Hetfieldinn Staff Member

    If you are using a portable tank, take the fuel pickup line out of the tank and make sure that it's tight. I had a 25 merc doing the same thing. Fine at idle, missed badly at higher speeds. After replacing everything I could think of, I checked out the tank, and the fuel pickup line was very loose. I secured it with a zip-tie, and it was fine.
     

  3. UFM82

    UFM82 The one others want to be

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    Did you take carb cleaner with a tube and spray it through EVERY passageway in the carb body or did you just spray the inside of the venturis? The high speed jet sounds to be clogged. That'd be my first hunch.

    Does it backfire or "sneeze" through the carb? Does it just bog down, lose power or actually miss?


    UFM82
     
  4. feetdown

    feetdown They call me "BIG POPPA"

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    It just misses violently...cleaned it thouroughly...The fuel pick up is fine Ive been runnnign another motor on the same tank till this 1 is fixed
     
  5. fishingguy

    fishingguy The Inferior Fisherman

    Maybe a vacuum line if you have one. Check hoses or replace with new clamps. In fact probably not a bad idea to replace all gas lines in the motor.
     
  6. Are you sure you have a 77. The ign systems between 76 and 77 are way different. If you have the model number it might help. It sounds more like ign than fuel to me but ???.
     
  7. feetdown

    feetdown They call me "BIG POPPA"

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  8. I agree with captk. Sounds like an ignition problem to me. Probably a coil or condenser. Good luck.
     
  9. feetdown

    feetdown They call me "BIG POPPA"

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    Im going to replace the coils but I can only find a part # on 1 of them..it is 582508. Does anybody know the part # on the other coil
     
  10. feetdown

    feetdown They call me "BIG POPPA"

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    Update..........
    replaced the coils, rebuilt the carb, and even fixed a leak in the fuel line...same results very bad miss...seems like now its even losing power, not alot but it seems different.....
     
  11. No expert here BUT. If this model uses points. Evinrude used to use two sets.
    High speed and low speed point sets. On mine I had to pull the flywheel with a wheel puller. Soon as we pulled the flywheel off the one set was obviously broke. Same syptoms as yours started fine idled great. Soon as I went to go over about 6mph it missed badly and no power.

    We installed a new high speed set of points and tested and she ran great. I had that rude for 11 years and that was the only problem I ever had with it.
     
  12. feetdown

    feetdown They call me "BIG POPPA"

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    ill check it out..thanks