Mercruiser no spark

Discussion in 'Gas Engines' started by Greg Davison, Jul 19, 2007.

  1. Greg Davison
    Joined: Jul 2007
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    Location: Sturgeon Bay, WI

    Greg Davison Junior Member

    Hi,
    A little help please. Just bought a 1976 Carver w/Mercruiser 888, 188 hp I/O and I am trying to get it back in shape. Sat in storeage for 10 years but was running when last out.
    I am not getting any spark and the two wires at the coil, tan in color become very hot? I am guessing somewhere something is shorting out and preventing power from getting to the coil? Any sugestions are appreciated.
    Also any help in other areas I should be aware of with a boat that has been sitting for so long? Thank you all very much.

    Greg
     
  2. redtech
    Joined: Feb 2007
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    Location: suger pine, ca

    redtech Senior Member

    check voltage going into the coil should be 6-8 volts if good move on to the pionts and condencer
     
  3. Greg Davison
    Joined: Jul 2007
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    Location: Sturgeon Bay, WI

    Greg Davison Junior Member

    Thank you for the specific response. I now have a weak spark out of the coil and to the plug. Last night I had a electrical meltdown at the battery with the mess of wires converging on the battery. I am thinking that this could have been a blessing in disquise and could lead me to discovering an overlooked draw on the ignition system developing the weak spark?? Any input? Thanks again, electrical systems on engines is my weakest link. Just can't seem to see those volts like you can a wore bearing.

    Thanks agian for your help and reply!
    Greg
     
  4. stonebreaker
    Joined: May 2006
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    Location: Shiloh, IL

    stonebreaker Senior Member

    Check the coil and plug wires. feel the coil wire, and if the wire feels "crunchy" underneath the insulation, it's time for a new set of plug wires.

    If the wires are getting hot, that would suggest too much amperage, not too little. Some ignition systems have a ballast resistor in line with the coil, might need a new one, or an internal short in the coil might be your problem, too. Coils, btw, are cheap - like 15 or 20 bucks.

    On a motor that has sat that long, seems like it would be a good idea to just do a major tuneup anyway - new coil, distributor cap and rotor, points, condensor, plug wires, plugs, vacuum advance spring, the whole deal.
     
  5. Greg Davison
    Joined: Jul 2007
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    Location: Sturgeon Bay, WI

    Greg Davison Junior Member

    Thanks PHd, The hot wires were from a short that occured in a mess of wires at the battery. I need to straighten that out so things are a bit more "together" at the battery. I think my feet were the culpret that moved some wires around and next thing I knew things were orange and smoldering good. I am hoping that once I go through sorting each circuit and straighten out the wiring at the battery that I find the cause of the weak spark. The whole turning over of the engine has sounded only 3/4 speed or so since I have taken ownership of this beauty. I do appreciate all the help that you and others can offer. Once I get the wiring under control and if that does nothing to help the spark than I am at the end of my ideas.
    You did mention a ballast resistor and I do have one outside of the coil somewhere at least according to the manual. I searched the wire between solenoid and coil and did not find anything interupting the path. Is this resistor on the leg from the ignition to the coil?

    Thank you all again. I really want to make this come back to life soon. I did preform a tune up as you mentioned.

    Greg
     
  6. gonzo
    Joined: Aug 2002
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    Location: Milwaukee, WI

    gonzo Senior Member

    The original coil might've been changed. Check if it says:"internal resistor"
     
  7. Greg Davison
    Joined: Jul 2007
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    Location: Sturgeon Bay, WI

    Greg Davison Junior Member

    External Resistor

    Gonzo, thanks for your reply. The old coil said external as does the coresponding new coil in the parts cataloge.

    Thanks and I sure do love the input I am receiving.

    Greg
     
  8. Greg Davison
    Joined: Jul 2007
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    Location: Sturgeon Bay, WI

    Greg Davison Junior Member

    Hey I got good spark at the plugs! Seems my electrical snafue last weekend
    did indeed help me. So far only the windshield wipers are not working but I got spark and hot at that.

    Now lets move on to fuel. I can not get it to fire so I pulled the fuel line to the carb. and cranked over the engine and nothing flowed. Where should I begin? First thought is fuel pump for me. Please remember that this boat has sat idle for 10 years with gas in tank. I did pump out old gas and yes I did put some new in.

    Thanks for any help...Together we are making progress!

    Greg
     
  9. stonebreaker
    Joined: May 2006
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    Location: Shiloh, IL

    stonebreaker Senior Member

    What kind of fuel pump do you have? Mecahnical or electic? That would be the first thing to check.
     
  10. Greg Davison
    Joined: Jul 2007
    Posts: 7
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    Location: Sturgeon Bay, WI

    Greg Davison Junior Member

    Fuel Pump

    It is a mechanical fuel pump on a 1976 Ford Small Block 302ci engine. Thanks for replying!
    Greg
     
  11. August Ice
    Joined: Aug 2007
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    Location: Biddeford ME

    August Ice Junior Member

    Did you try sanding off the magnets under the flywheel?
     
  12. jimslade
    Joined: Aug 2005
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    Location: north Markham

    jimslade Senior Member

    A carb that sits for 10 years, needs a rebuild job, at least the float and needle set. Check the antisyphen valve at the tank. Boats should not sit for ten years without running the engine for a short time every year.
     

  13. Greg Davison
    Joined: Jul 2007
    Posts: 7
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Sturgeon Bay, WI

    Greg Davison Junior Member

    Fuel Pump

    I just pulled off the fuel pump from my old boat and found white granules in the housing of the pump. Seems to be full of the stuff. Any idea of what that could be from? I am shopping for a new fuel pump.
    Thanks,
    Greg
     
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