40 hp. Mercury

Discussion in 'Bubba's Outboards' started by Kennie G, Jul 31, 2006.

  1. Kennie G

    Kennie G New Member

    Messages:
    12
    State:
    Iowa
    My father-in-law has a 40 hp. mercury that cranks over but won't fire. We have non-experts tell us that it is the switch box or the ( stater ) and to change them both if you change one. Is there any way to test these parts at home. We have some auto mech. knowledge but no outboard, The nearest outboard shop want over a hundred to just look. The motor is a 1983 but I don't have any other info on hand at the moment. Thanks Kennie
     
  2. Bobpaul

    Bobpaul New Member

    Messages:
    3,039
    State:
    Supply NC
    There is a series of cranking output test to check voltage, also some tests to check the ohms/resistance in some components of the ignition system.

    Mercs do mostly ohm tests, but if you've got a peak reading volt meter, you can test voltage going from the switch box to the coil, or voltage coming from the stator to the switch box.

    And no, you don't change both if one is bad.

    If Bubba doesn't post the test numbers and wires to check, I'll try to get it for you tomorrow.

    Oh BTW, do you play the sax?
     

  3. Kennie G

    Kennie G New Member

    Messages:
    12
    State:
    Iowa
    No I don't play the sax, I have a more useful talent, I can fish. LOL Are these parts located under the flywheel, or are they visible, or at least the wires to check. We would like to get this fixed without spending a mint so all help is very much appreciated! Thanks Kennie
     
  4. Fire-Man

    Fire-Man Member

    Messages:
    35
    State:
    South Carolina
    Kennie
    I am no mechanic but I own a 1984 50hp Mercury. My Mercury had a Extra switch that was installed when I bought it that would shut the motor off if I was throwned from the boat. Is it possible this motor has one? It will not fire a lick if it has one and the cord that attaches to the switch and the driver is not in place. My motor also has a tilt switch that would cut the motor off if the motor hit a log and it tilted to far out the water----you need to check for this switch(mine was bolted up under the hood I think with one black wire attached to it with the wire going to the electronic ignition on the side of the motor), it might be out of adjustment---mine acted up and shut my motor off riding down the river. I did have to replace the electronic ignition piece because my motor started skipping. If I were you and this motor has been sitting---I would loosen all the wires on the electronic module one at a time---clean and re-instal--check these other things. Good Luck!! Randy

     
  5. Bobpaul

    Bobpaul New Member

    Messages:
    3,039
    State:
    Supply NC
    Why do I always forget the kill switch.

    Thanks Randy for bringing that up.

    Under the hood, you'll find a black wire with a yellow stripe. Trace it to a connection and seperate the connection to see if the kill switch is grounded out. If it starts after you break the connection, you've found the problem. To shut the engine off, reconnect.

    All the other wires will be accessable to test.
     
  6. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    Alright kenney tell me the year of this motor or post the serial number so I can see what we have here and get you some numbers to work with.

    That switch that he is talking about is a kill switch.
     
  7. Kennie G

    Kennie G New Member

    Messages:
    12
    State:
    Iowa
    There is a toggle type of kill switch up next to the console. I hope the problem is as simple as a bad switch, that way we don't pay a repair shop $500+ for them to replace a $4 part. I'll get the numbers on here tomarrow the boat is at his house. You guys are good just a few hours and all these responses. Thanks again. Kennie
     
  8. Fire-Man

    Fire-Man Member

    Messages:
    35
    State:
    South Carolina
    Sorry I was thinking Tiller Handle, But Maybe it is just a Bad switch or loose connection------Let Us Know!!! Good Luck!! Randy

     
  9. elalr

    elalr New Member

    Messages:
    193
    State:
    warsaw missouri
    if by chance it is the switch box try psepmarineparts.biz. i saved a couple hundred dollars on mine.
     
  10. Kennie G

    Kennie G New Member

    Messages:
    12
    State:
    Iowa
    The serial # 6053542 the cover of the motor says thunderbolt ignition it is on a bass tracker II boat. My buddy is a mechanic so we have access to voltage and ohm meters if we know what to start testing. My father-in-law said he had a stator put on about 10 years ago and only has about 30 hours on the motor since ( most of the local puddles are electric only ) the motor was running then quit and hasn't started since. Thanks for helping guys. Kennie
     
  11. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    Kennie some where on that motor there is a saftey switch around the recetfier that looks like a condenser that might be the problem if it just shut down on him.
    Is this a two cylinder or a three cylinder. I have found those in my books but it has three different kinds of ing systems for the thunder bolt system on them. Does it have the blue coils.
     
  12. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    Alright kennie before we go to all this posting test I want you to look on the terminal box located on that engine. Should be toward the back and is long black with a bunch of wires going to it. There is a orange wire hooked to it and I want you to take it loose. It will run in one direction to the switch box and in the other direction to the ing switch When you get it disconnected then try cranking the engine to see if you have fire to the cylinders. Now don't hold those plug wires out to far away from the plug or it might overload the coil and burn it out. I can send you a picture of a home made spark tester if you need it.

    What were are doing here is the process of elimination. The switch box can't be tested with an ohm meter so we will test all components as we go and when all those check good then it will be the switch box by default. If we get it started before then then we know switch box is good.
    When you disconnect the orange wire make sure you have fuel to the engine if you going to see if it will start. If it starts the just touch the orange wire back to the terminal and it will kill it.