40hp mercury only firing on 2 cyc???

Discussion in 'Bubba's Outboards' started by smells like old liver!, Jul 12, 2007.

  1. smells like old liver!

    smells like old liver! New Member

    Messages:
    95
    State:
    kentucky
    Help!! I've got a 1989 40 hp mercury it's only firing on the top 2 cyc. yesterday I put a volt meter on the bottom 2 cycl. it was getting very little voltage not enough to spark a plug. I was messing with my battery checking my lights. the next time I turned it over it had good fire on all 4 cyc? today I tried to start it and again no fire on the bottom 2 cycl. whats up with this?? also some times you can just turn the key on and get a warning signal sound, start it and it quits??
    thanks
     
  2. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    Randy I have some tests written down that you can do on this to try to figure it out. Sounds like you have something loose or shorted out some where. I don't have time to post the right now but will this evening.
    In the mean time check for loose connections and look for any that might be corroded. It don't take much corrosion to stop the ground on an out board.
     

  3. jim

    jim New Member

    Messages:
    2,579
    State:
    Jacksonville NC
    Check your battery and I mean load test it.It can show 12 volts and not have enough amps to fire all the cyls.Also you should get a warning sound if you just turn the key as it should be testing the engine systems or oil res.The sound will stop when you start the engine.Or as Bubba says you might have a bad connection,short or drain somewhere .I always start first with the battery and make sure it can do its job.:big_smile:
     
  4. smells like old liver!

    smells like old liver! New Member

    Messages:
    95
    State:
    kentucky
    thanks guys I'm going to look at it today.. so any help you can send my way would be great.
    thanks
     
  5. Big Sam

    Big Sam Well-Known Member

    Messages:
    4,344
    State:
    Booneville AR
    Name:
    Sam
    I got a 40 too. Check the wires where the plug in by the starter. They are bad about vibrating apart from each other. Had this happen in the past.
     
  6. smells like old liver!

    smells like old liver! New Member

    Messages:
    95
    State:
    kentucky
    thanks sam, looks like someones wraped black tape around that plug. I'll check it out.
    thanks
     
  7. smells like old liver!

    smells like old liver! New Member

    Messages:
    95
    State:
    kentucky
    Boat! you keep messing with me and I'll blow holes in you that you can run your fist in!:angry:

    Boat all most for Sale:
     
  8. peewee williams

    peewee williams New Member

    Messages:
    3,111
    State:
    Pembroke,Georgia
    If you want to be noticed and remembered for a long,long time,blow that hole while you are in the middle of the lake or river!I had a friend who did that 35 years ago.He has been dead for 20 years.We still talk of Woodrow and his "Holy Boat".Frustration is part of owning a boat and motor.Please let us know what you find out so we can learn with you.Luck! I love you Brothers and Sisters.peewee
     
  9. smells like old liver!

    smells like old liver! New Member

    Messages:
    95
    State:
    kentucky
    Hey sam, I messed with the wires where they plug together and got fire! looks like someone has been into them before me. but the motor still sounds the same. I'm also thinking it may not be getting enough fuel to the bottom 2 cyl. going to run a compression test tonight and pull the carbs off.. if this dont work can I make 2 cylinder motor out of this? :confused2: I'll be loading my 44mag. in about 2 hr. I'll post the video..............
     
  10. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    Randy if those wires are bad I would replace them all the way through because if the spit fire any where along the line it will make them run rough.
    I'll find those test now and post them for you. Sorry about being so slow but have been busy fishing these last two days.:wink:
     
  11. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    Check the Trigger. Disconnect the Brown/white and the Brown/Yellow wires from the switch box. Test the resistance between them. You should have 750-1400 Ohms. If not you have a bad trigger. If you do get these readings then Check voltage going ti coils from the switch box. Each coil should have 180V+.