Whats Wrong With My Motor-Please Help!

Discussion in 'Bubba's Outboards' started by jdw123, Aug 15, 2008.

  1. jdw123

    jdw123 New Member

    Messages:
    60
    State:
    texas
    Ok, I'm really getting frustrated with working on my engine. It got to where it is hard to start and once I do get it started it will idle at high rpms but when I cut it down to low idle it dies. I rebuilt the carb and cleaned it out extremly well and put new gaskets on it and tuned it according to the manual and replaced the diapraghms on the fuel pump. all my fuel hoses are tight. I put a new CDI unit and ignition coil on it. New plugs correct gap. Still dies at low idle. I noticed the exaust gaskets were really corroded and water is just sitting in my lower cowling. could water be getting into the powerhead? would this cause hard starting and to die at idle? also, the compression is very good.
     
  2. AwShucks

    AwShucks New Member

    Messages:
    4,532
    State:
    Guthrie, Oklaho
    Two things would be helpful.... 1) Make, model, horsepower, and possibly serial number. This will enable Bubba and the other experts to look at shop manuals if they don't have the answer at the top of their head. One think I have found which causes poor idling is low compression. Run a compression test and post those results. Hope that's not your problem though... it gets expensive. LOL. Possibly it is just a bad head gasket. I have a 50 HP Johnson which gave me those same conditions.
     

  3. Wvawitrado

    Wvawitrado New Member

    Messages:
    463
    State:
    California, Fresno
    Iboats.com is your cure my friend they will take care of you with this in minutes!!!!
     
  4. jdw123

    jdw123 New Member

    Messages:
    60
    State:
    texas
    its a 1989 yamaha 15hp. compression was 120 in each cylinder.
     
  5. runabout199

    runabout199 New Member

    Messages:
    121
    State:
    Cartersville, G
    dont know if this applies to you but i was having same trouble out of my old evinrude 9.9 . is your motor tiller steer? on my motor there is a plate that is bolted under the fly wheel that when you turn your handle {guess it would be same maybe for steerin wheel boats also} that was wore out. i built it up with some jb weld to get it where when you turn the handle the carb will open. also check your fuel pump and filter. hope this helps. ill try and post some pics of that plate
     

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  6. x smokin joe

    x smokin joe Well-Known Member

    Messages:
    2,076
    State:
    Monclova,
    Name:
    Joe
    This might seem kinda simple but thats what mine was doing and it was water in the fuel. Drain the tank and take bowl off carb and dump might be all it needs.
     
  7. jdw123

    jdw123 New Member

    Messages:
    60
    State:
    texas
    changing the fuel was one of the first things i did. as i stated before there is water sitting in my lower cowling and i wonder if a leaking exaust gasket will cause water to get into the powerhead and cause hard starting and to die a low idle. as far as the plate under the flywheel, that plate is designed to advance or retard the timing. all you have to do is screw in the idle stop screw to get the throttle to stay open.
     
  8. slimdaddy

    slimdaddy Well-Known Member

    Messages:
    2,600
    State:
    Nelsonville, Oh
    Name:
    Keith
    did you look at the plugs to see if there is water gettin in probaly be water beads on them if water is going into the cyl and where is the water coming from in the cowling
     
  9. jdw123

    jdw123 New Member

    Messages:
    60
    State:
    texas
    i checked the plugs but its kinda hard to tell if water is getting into the cylinders. the water looks like its coming from the exaust cover but im not real positive. i know the exaust cover gaskets are really corroded so is the head gasket.
     
  10. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    If it is getting exhaust fumes under the hood while trying to run there ain't no way its going to run right. A bad head gasket will make one run rough and take the plugs out and if they are real clean then it is spraying water on them and water doesn't burn to evenly. Do a spark test and a compression test and get back to me.
     
  11. jdw123

    jdw123 New Member

    Messages:
    60
    State:
    texas
    ok, checked the spark to the plugs with a spark tester. Both had a nice blue spark. re-checked the compression and again 120 in each cylinder. also, tried running it with the hood off and still same problem. the plugs were clean but they are new plugs though.
     
  12. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    Pull the hood off and run it in the dark and see if any of the wires are jumping fire and check the grounds to the coils and remove and clean the grounds good.

    Try choking it real quick when it comes back ti low idle. It sounds like the low idle circuit is stoped up or it doesn't have enough fuel in the bowl to complete the idle.
     
  13. jdw123

    jdw123 New Member

    Messages:
    60
    State:
    texas
    ok, i tried choking it when its turned to low idle before it dies and it still dies. i raised the float height and still the same thing. it has to be water getting in the cylinders. i've tried absoutly everthing you can think of and nothing works. and it still hard to start. when i adjusted the float height i cleaned the carb out again for the fourth time and ran a small wire through every little hole. so i know the carb is super clean. no wires are grounding out. i put a new cdi and ignition coil on it also. but im thinking that since my head gasket is really corroded that is a sign of water getting in there.
     
  14. x smokin joe

    x smokin joe Well-Known Member

    Messages:
    2,076
    State:
    Monclova,
    Name:
    Joe
    Since you keep insisting on it being a head gasket, change it.
     
  15. jdw123

    jdw123 New Member

    Messages:
    60
    State:
    texas
    i never insisted it was the head gasket. i said it might be the exaust gasket leaking water into the cylinder causing the head gasket to corrode. i tried taking the exaust cover gasket off, but the bolts are corroded and the heads of one of them broke off. so im going to have to take it to a machine shope and have them redo the threads. i guess water is mixing with the fuel causing hard starting.