Evinrude idles high then low

Discussion in 'Bubba's Outboards' started by catfisherman369, Oct 24, 2009.

  1. catfisherman369

    catfisherman369 Floyd

    Messages:
    4,944
    State:
    Nashville Il.
    I have an old evinrude 50 horse . Not sure the year . The problem is it will start easy and idel fine , but if you give it gas it will die out , unless you hold it at full throttle then it revs high then low then high then low and will do this the whole time while holding it at full throttle . Anywhere inbetween idel and full throttle it dies . Any ideas ?
     
  2. catwhisper

    catwhisper New Member

    Messages:
    456
    State:
    georgia
    start with the basics, air vent in tank open, holes in lines, then check the carbs.
     

  3. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    That is called surgering. Do as posted above and take the top off the fuel pump and see iof it has any trash in it.
     
  4. Bobpaul

    Bobpaul New Member

    Messages:
    3,039
    State:
    Supply NC
    I've been going out with a fella that's got a 97' 30 hp evinrude.

    It started and ran very good, but it would start to surge after it got hot. Everything I read up on says it was a fuel related problem. Don't believe everything you read.

    After going through the complete fuel system and a new fuel pump, it still did it. Sometimes it would happen while running wide open, and sometimes after idleing while pulling crab traps.

    Two things I noticed were, it had NGK plugs in it, and it would produce steam, but still put out a good water stream.

    I replaced the plugs with the proper Champion plugs and installed the first replacement water pump ever for this engine.

    No more surging/missing type running. Don't rule out overheat and siezing pistons, and older OMC engines, use Champion plugs. Switching out NGK for Champion has cured the miss in another older 25 hp Johnson I worked on also.