1968 18h Evinrude idle problem.

Discussion in 'Bubba's Outboards' started by Stainless, Jul 9, 2006.

  1. Stainless

    Stainless Member

    Messages:
    185
    State:
    Ft Smith, AR
    I recently purchased me a flat bottom with an 18 horse Evinrude. There were a few problems with the motor before I bought the boat. When I was trying the boat out it ran great and then all of a sudden I had to choke it when running wide open to keep it running. We discovered the problem which was the gasket fell apart in the bowl and it was sucking too much air. We made a temporary gasket out of cardboard and it was tuned up and ran great, even idled real good. I was told if I went and bought a gasket kit that he would change it before the purchase was final. We did that and it ran fairly well the first time it was taken out but the second time I started having problems with it. It's hard to start in neutral. It's as if it's not getting enough gas to keep it running. I have to pull three or four times and then hurry up and stick it in gear and from there it runs great. But when I go to slow down I have to keep revving it up and when I stick in in neutral it dies. I know there is an idle/air mixture screw on it but I really don't seem to notice a difference when turning on it other than that the motor starts crapping out. Other than that I don't see any other screw to adjust the idle. There is a bushing that looks a little wore out that I thought might not be allowing enough push on the butterfly but this is the first boat motor I've ever owned or attempted to work on. Any ideas from the professionals? A few pics attached of the actual motor. Thanks
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  2. Bobpaul

    Bobpaul New Member

    Messages:
    3,039
    State:
    Supply NC
    Great pics Stainless. I wish everyone had a camera.

    If your not getting much response when you adjust the idle air mixture, you might need new packing around the needle shaft.

    That bushing your pointing to is a cam follower roller. It rides on the timer base cam and does what you say, advances throttle with advanced timing.

    Ask if new packing was put in. Be sure your fuel is water free. Get a spray bottle with your fuel mix in it and spay around the carb to check for air leaks, and put an inline filter in your fuel line.

    If your using a metal tank, be sure it's rust free.

    You need to get it right. When you hurry up and jam it in gear, your wearing out the gears and clutch dog
     

  3. Stainless

    Stainless Member

    Messages:
    185
    State:
    Ft Smith, AR
    Thanks for the really quick response Bobpaul!
    I'm pretty sure that there was no packing put in and the guy I purchased it from has since moved on to another job that keeps him tied up so calling him is probably not an option. As of right now the idle/air is screwed all the way in clockwise. Is there a way to tell if "packing" needs to be added or changed?
     
  4. Bobpaul

    Bobpaul New Member

    Messages:
    3,039
    State:
    Supply NC
    If it's all the way in and it still runs, you've got an air leak some were. Remove the needle and inspect the tip for distortion or a bent tip.

    Get a replacement if it's messed up and new packing.

    Before getting into anymore problems, do a compression and spark check to be sure it's banging on all cyl's.
     
  5. Stainless

    Stainless Member

    Messages:
    185
    State:
    Ft Smith, AR
    I unscrewed it all the way out to inspect it and it still has a really sharp point. I screwed it back in and took it back out and found a peice of trash on it the size of a grain of pepper. Screwed it back in and it idles great now :lol: I noticed that the motor doesn't have an air filter and I'm guessing that might be normal since there isn't alot of dust on the water so would this trash have gotten in there through the air or through the fuel? I'm definitely going to take your advice on the inline fuel filter either way.
     
  6. Bobpaul

    Bobpaul New Member

    Messages:
    3,039
    State:
    Supply NC
    I'd suspect the fuel has trash in it. Drain the carb, put in the filter, purge the line with filtered fuel and you might consider replacing the fuel lines. They come apart on the inside from age and our newly formulated gas designed for automobiles, and trash a carb.
     
  7. Stainless

    Stainless Member

    Messages:
    185
    State:
    Ft Smith, AR
    Thank you for your help. It's really a great that you offer your knowledge and are so willingly to help out the members of the BOC.
     
  8. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    Dad gum Bob you are on a roll here.:lol: :lol:

    Bob is right on with that fuel line needing replaceing. And that was some awsome pictures.:big_smile:
     
  9. Bobpaul

    Bobpaul New Member

    Messages:
    3,039
    State:
    Supply NC
    Heck Bubba, just jump in whenever you feel like it.

    Gotta hit a roll every once in awhile.
     
  10. jim

    jim New Member

    Messages:
    2,579
    State:
    Jacksonville NC
    I'm no expert and probably have no business jumping in here BUT if I were purchasing any kind of used outboard engine this is what I would do.WE have posted many times about todays modern gasolines,ie they are basically dirty and deteriorate quickly as in within weeks.So I would first drain all fuel.I know its tempting to use that fuel already in the tank but get rid of it (Correctly).Buy new gas and by the way look at that fuel tank.If its old and corroded or rusted it is time for a new one.When you buy the new gas put in STABILIZER,I recommend PRI-G but Stabil and others work.Do IT EVERYTIME you add fuel, its cheap insurance.Then I would flat out replace the fuel line assembly and primer bulb.That way you know you have good fuel,a good tank and line assembly that is airtight.Then you can continue with the diagnosis if necessary,but I'll bet that will cure most of the problems.Many will require a good carb rebuild or cleaning at least.Use some form of cabon remover a couple of times a year also although many of the stabilizers have added this capability also.Good luck but remember Good performance of an outboard is not a matter of luck but proper and continous maintenance.
     
  11. Stainless

    Stainless Member

    Messages:
    185
    State:
    Ft Smith, AR
    Good advice as well Jim. Thx. The fuel line is new and the gas tank is plastic. I stopped by the local AutoZone today and picked up an in line fuel filter, now I just have to drain and flush the tank and cut the line for the filter. I'm guessing that it might be better to have the fuel filter between the tank and the primer bulb or the other side? On another note, would flushing the tank with diesel be alright as long as I made sure I got it all out?
     
  12. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    Flush it with paint thinner and alcohol and then let it air dry for a while.