40hp merc Thunderbolt oil leaking

Discussion in 'Bubba's Outboards' started by vegasryder, Jul 2, 2007.

  1. vegasryder

    vegasryder New Member

    Messages:
    324
    State:
    illinois
    Just started the boat out today after replacing the water pump.The problem i`m having now, is that oil(mocha colored)is coming out from where the propeller connects to the lower unit.Not just slow drips but leaking.I just changed the gear oil and i know it doesnt change the color that fast.Any help or suggestions would be greatly appreciated...Thanks

    Merc 40hp serial #05992196
     
  2. vegasryder

    vegasryder New Member

    Messages:
    324
    State:
    illinois
    I ran it a second time after i posted the message.It stopped leaking to mocha liquid...I`m still baffled on what could of caused it?Is it also normal for the prop to turn while its in neutral?
     

  3. glenmorebuckman

    glenmorebuckman New Member

    Messages:
    153
    State:
    Caneyville, Ken
    Sounds like a bad seal to me. The change of color is from water entering into the gear case. Not a good idea to be running it until it's fixed.
     
  4. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    That most likely is unburned fuel coming out there. If you are real worried about it take the drain plug out of the bottom and look at the color of the oil but if you will put some of the goo on your finger tip and smell of it you will see that it smells different then lower unit oil.
    If the lower unit oil is good take you some seafoam and put it in your tank and run that baby like you stole her. In the water on course and not on land.

    You are running NGK plugs in it aren't you?
    You will get a little prop turn from the exhaust coming thru it on those old dogs.
     
  5. vegasryder

    vegasryder New Member

    Messages:
    324
    State:
    illinois
    Yes,i am running NGK plugs on it.I know the fuel that was in the motor was from the previous owner...and lord knows how old it is.So i threw in some new fuel/oil mix and ran the motor.Thats when the color came out.The second time starting it,it didnt do it.So i`ll go ahead and check my lower unit oil to see if thats it.Hopefully your rite Bubba...i`m running out of funds trying to work on this boat.

    Also,the throttle control is a little hard to put into gear...Is there something i did wrong with putting the lower unit back together?I put the gear into neutral,when i pulled it down.The only thing i did different is that i turned the prop a little to slide it back into the housing when i assembled it back in.
     
  6. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    Does it shift into reverse okay.
     
  7. vegasryder

    vegasryder New Member

    Messages:
    324
    State:
    illinois
    Your rite as usual,Bubba.I opened the drainscrew alittle bit to see what comes out,and the gear oil is the same color as it was when i put it in...I then smelled the sludge that came out,and it smelled like gas.As for the throttle,i`m going to see what wrong with it a little later when the wifey gets home.Thanks!!!