40HP mercury

Discussion in 'Bubba's Outboards' started by rudepossum, Jul 23, 2008.

  1. rudepossum

    rudepossum Well-Known Member

    Messages:
    1,432
    State:
    Missouri
    OK: My father in law has a 2 year old pontoon with a 40 hp Mercury that will not idle. Was not winterized in anyway this last winter. He put fresh gas in with last years gas. We can get it to run at high idle but will not idle at less than half throttle. We cleaned the carbs out which helped it run a little smother at high idle, but still won't idle at less than half throttle. We also drained all the gas from the system when we cleaned the carbs. So now i am at a loss. Ran gr8 last time out last year. Hope it is something Easy since it has only been ran 3 times this year for just a couple minutes at a time trying to see if we had it fixed. thx for any ideas that might help. rudeopossum, (thats rude--- opossum not rudeo possum lol)
     
  2. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    Check all the fuel lines for air leaks. Those round connectors for merc were nortious for leaking and sucking in air. Also when was the last time you changed the plugs and checked the fuel lines for deteration on the inside.
     

  3. rudepossum

    rudepossum Well-Known Member

    Messages:
    1,432
    State:
    Missouri
    New plugs and fuel filter, yes.) The first time they put it in the water it would not stay running at all, so we pulled it back up on dry land and it had some gas coming out down below the cowling some where. We could not see where it was coming from. And has not leaked a drop of anything since. Any way to check for air leaks? Any way thx for your reply Sir........ rudeopossum
     
  4. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    I have never really checked for air leaks I always from habit replaced all my fuel lines and connectors if they are 2 years old or older.. That fuel was either coming from a over loaded carb or from the fuel pump. I would susspect a carb, those merc carbs are finicky to say the least. When you had the carb off did you run a small wire or use compressed air to blow through the little jets and tubes. It sounds like you have a low idle circut stopped all the way up. I would remove and soak over night and clean real good and rebuild them.
     
  5. rudepossum

    rudepossum Well-Known Member

    Messages:
    1,432
    State:
    Missouri
    Thank you for the advice Sir. I will take them back off and give it a try.