Motor idles worse in the water.

Discussion in 'Bubba's Outboards' started by wylie catter, Jul 8, 2008.

  1. wylie catter

    wylie catter New Member

    Messages:
    675
    State:
    South Carolina
    My 93 mercury 40hp will idle all day long with a water hose on it in the yard, but it doesn't idle long in the water. It acts like it has more of a load on it just being in the water.

    Do you think I need to replace my impeller on my water pump.

    I was also wondering where can I buy new carbs for the same motor. I can't find new ones anywhere on the web. If I don't eventually get all the little bugs worked out I'm going to buy brand new ones or get another motor.
     
  2. M.Magis

    M.Magis Member

    Messages:
    45
    State:
    SE Ohio
    That's because it does. The idle has to be set while in a tank or on the water for that reason. Sounds like yours are just dirty or simply not set right. I don't think buying new carbs is the answer.
     

  3. wylie catter

    wylie catter New Member

    Messages:
    675
    State:
    South Carolina
    I have set the idle in the water. And totally rebuilt both carbs, for the second time. There are other problems with the carbs. Gas leaking sometimes for no apparent reason and bad cranking problems. I'm pretty fed up with those carbs.

    The adjustment on the idle linkage is pretty much maxed out. That's tells me somethings wrong.

    And sometimes it does idle good in the water. Just not for long. No longer than 2 or 3 minutes and it cuts off.
     
  4. boliver

    boliver New Member

    Messages:
    198
    State:
    Rudy Ark
    i kinda had the same problem. mine idled rough or died when it was nt warmed up and still rough after warmed up. I overhauled and cleaned carbs. it was better but still not good. I took it to a mechanic and he looked at the new plugh I had put in and immeaditely diagnosed it was running rich. he reset the float level and it ran and idled great.
     
  5. Bobpaul

    Bobpaul New Member

    Messages:
    3,039
    State:
    Supply NC
    Merc carbs are extremely finicky, and gas leaks for a reason.:wink:
     
  6. wylie catter

    wylie catter New Member

    Messages:
    675
    State:
    South Carolina
    There's a little box that the fuel line goes into on the side of the motor and it comes back out the top. I assume this is a fuel pump?

    Can I rebuild it? I'm going through a process of elimination.
     
  7. AwShucks

    AwShucks New Member

    Messages:
    4,532
    State:
    Guthrie, Oklaho
    Yep, Evinrude fuel pumps can be rebuilt. Parts at the auto supply stores in my town run pennies over $17.00. Again, it does not take a rocket scientist to rebuilt the pump, so have at it. I would almost bet that when you disassemble the carbs, if you measured the height of the float you will find it off substantially or the shut off plunger (can't remember it's name right now to save my life - LOL) is badly worn.
     
  8. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    Where does the fuel leak from and did you soak those carbs over night and install a new kit or did you just say they look good and reassemble them. As for idleing rough under a load if you don't have a book and understand how to set those fineky red headed carbs then you won't ever get them right.
    There are numerous things that won't let a engine idle right under a load. What trouble shooting have you done and what and where did you get your procedure of setting the carbs,
    I wouldn't rebuild that fuelpump I would replace it with a new one.
     
  9. Pacman

    Pacman New Member

    Messages:
    141
    State:
    South Carolina
    I had one that acted this way. It was worn out...compression low. It would run good if you fed it enough gas, but just wouldn't idle well.
     
  10. cattoon

    cattoon Member

    Messages:
    199
    State:
    alabama
    are you feeding from a portable tank or on board tank? if portable there is a screen on the pick up tube that can clog and mine would run good at higher throttle but wouldn't pull fuel at idle for longer than a couple of min. something else to try is seafoam at 2oz to the gallon of fuel mix, and run the heck out of it, could check compression and make sure there isn't a prob with rings. My bet is float setting in carb, or a sticky needle in the carbs, and merc carbs are a bear to get set. try the seafoam before tearing into the carbs again, may be a little trash or varnish in there from the fuel line after the rebuilds, and you can check to make sure there aren't any air leaks loose clamps on the fuel hose