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  1. #1

    Default Mercury running (lack of power)problem+voltage regultor

    Hi

    just Serviced my 50 EFI 2006 because did not charge battery. New alternator and regulator was changed.
    today when driving at ~ 2500rpm the engine started to run bad, like 1-2 cylinders out of game? But after couple minutes it came back to normal. Continued with righ rews and
    no problems. but when i came to Dock and released the speed to ~2500rpm it started again after some minutes driving? But now it did not fix by itself and runs all the time like this.
    I notice that lack of power is huge.
    i also measured the voltage at battery when engine idling, 20V??
    can these be connected together or do i have bad luck. New regulator gets broken? Changed the plugs but did not help for running issues.
    I appreciate any help!

    jake

  2. #2

    Default Re: Mercury running (lack of power)problem+voltage regultor

    Don't run that engine until you fix the issue. 20V is going to cause some damage real quick. It is 99.9% the rectifier/regulator. replace it.

    I know you said you replaced it already, but I think possibly you might have a bad battery which in turn wrecked the regulator. Buy new battery and regulator. Or take old battery to shop and load test.

    cheers

  3. #3

    Default Re: Mercury running (lack of power)problem+voltage regultor

    Quote Originally Posted by Gavin27 View Post
    Don't run that engine until you fix the issue. 20V is going to cause some damage real quick. It is 99.9% the rectifier/regulator. replace it.

    I know you said you replaced it already, but I think possibly you might have a bad battery which in turn wrecked the regulator. Buy new battery and regulator. Or take old battery to shop and load test.

    cheers
    thanks for reply. How could bad battery cause this? I charged it and it showed 12,85V and at least it runs starter fine.

    can regulator cause the running issue?

  4. #4

    Default Re: Mercury running (lack of power)problem+voltage regultor

    Quote Originally Posted by Jake82 View Post
    thanks for reply. How could bad battery cause this? I charged it and it showed 12,85V and at least it runs starter fine.

    can regulator cause the running issue?

    A bad cell in the battery can cause overcharging. Start there. Go get your battery load tested. They will do a load test on it. If you're getting 20V your regulator/rectifier is also bad. Yes its normally bad reg or battery for overcharging.

  5. #5

    Default Re: Mercury running (lack of power)problem+voltage regultor

    Quote Originally Posted by Gavin27 View Post
    A bad cell in the battery can cause overcharging. Start there. Go get your battery load tested. They will do a load test on it. If you're getting 20V your regulator/rectifier is also bad. Yes its normally bad reg or battery for overcharging.
    i tested the battery, reason for 20v was my volt meter tool. Gave 50v in my car battery . So it was broken, got a New one and boat charges normally, huh.
    But i still have the running problem. Got instruction to test the fuel pump by pumping the ”ball” in fuel line. if helps could be the fuel pump, Did not help.

    could it be a pole? One of plugs were abit wet when i changed the plugs in rush yesterday. Damn i forgot to test the plug if it gives spark. I do that during weekend, if do not give spark then maybe pole? But if gives spark then i am confused

    any help and tips appreciated.
    Last edited by Jake82; 05-14-2021 at 10:34 AM.

  6. #6

    Default Re: Mercury running (lack of power)problem+voltage regultor

    Quote Originally Posted by Jake82 View Post
    i tested the battery, reason for 20v was my volt meter tool. Gave 50v in my car battery . So it was broken, got a New one and boat charges normally, huh.
    But i still have the running problem. Got instruction to test the fuel pump by pumping the ”ball” in fuel line. if helps could be the fuel pump, Did not help.

    could it be a pole? One of plugs were abit wet when i changed the plugs in rush yesterday. Damn i forgot to test the plug if it gives spark. I do that during weekend, if do not give spark then maybe pole? But if gives spark then i am confused

    any help and tips appreciated.
    Well that's some good news at least. I would try running the motor on a seperate tank with fresh gas and filter. Then I would get a timing light and test each cylinder for spark. If you find one is not sparking change coil + plugs. I would just change all the plugs at that point since they're pretty cheap.

    If you have spark on all cylinders and you changed the plugs, it would have to be stator or fuel delivery system. Sometimes fuel lines can collapse, or get tiny holes in them that allow air.

    My bet is on ignition coils. Good luck

  7. #7

    Default Re: Mercury running (lack of power)problem+voltage regultor

    Quote Originally Posted by Gavin27 View Post
    Well that's some good news at least. I would try running the motor on a seperate tank with fresh gas and filter. Then I would get a timing light and test each cylinder for spark. If you find one is not sparking change coil + plugs. I would just change all the plugs at that point since they're pretty cheap.

    If you have spark on all cylinders and you changed the plugs, it would have to be stator or fuel delivery system. Sometimes fuel lines can collapse, or get tiny holes in them that allow air.

    My bet is on ignition coils. Good luck
    Hi

    sorry dumb question. Testing with timing light: so if not blinking it is broke? I will test tomorrow.

    Also have each cylinder a own coil( there are 4 black units and a own spark plug wire), i mean one of them could be out? They are not connected to each other some way?
    Last edited by Jake82; 05-14-2021 at 03:33 PM.

  8. #8

    Default Re: Mercury running (lack of power)problem+voltage regultor

    Quote Originally Posted by Jake82 View Post
    Hi

    sorry dumb question. Testing with timing light: so if not blinking it is broke? I will test tomorrow.

    Also have each cylinder a own coil( there are 4 black units and a own spark plug wire), i mean one of them could be out? They are not connected to each other some way?

    Yes you should see a light for each time the coil sends current to the spark plug. Make sure you google how to use the timing light you have if you don't 100% know.

    Yes you will see with the timing light which is not sending a signal, then replace that coil. You can also test the coils, just YouTube how. I really think it is the coils. Depending on price, id just replace them all. If one is gone the others might not be far behind.

    This really could be as simple as a new spark plug though. Change all of them first then try it out. Run it for a min, then turn off, remove the plug and inspect to see if its dirty. If its dirty and gassy its not sparking. If not sparking change coil. Start there and then let me know. cheers

  9. #9

    Default Re: Mercury running (lack of power)problem+voltage regultor

    Quote Originally Posted by Gavin27 View Post
    Yes you should see a light for each time the coil sends current to the spark plug. Make sure you google how to use the timing light you have if you don't 100% know.

    Yes you will see with the timing light which is not sending a signal, then replace that coil. You can also test the coils, just YouTube how. I really think it is the coils. Depending on price, id just replace them all. If one is gone the others might not be far behind.

    This really could be as simple as a new spark plug though. Change all of them first then try it out. Run it for a min, then turn off, remove the plug and inspect to see if its dirty. If its dirty and gassy its not sparking. If not sparking change coil. Start there and then let me know. cheers

    Hi, pole it was. I checked with ignition light. Only 1 gave light for lamp.
    i unplugged the working pole and tought the engine would not start but it did, but really badly.
    maybe some of remaining poles gives weak spark or something and lamp do not recognise that?
    anyway, better change those all. Any ideas why they went
    down, age? Or maybe can be realated to the previous problem when my regulator was broken?

    jake

  10. #10

    Default Re: Mercury running (lack of power)problem+voltage regultor

    test your coils before replacing them so you know 100% It could also be a few other things along your ignition system. Make sure you inspect and replace any old wires from things you've replaced. Ive seen old parts get replaced and when they move the wires they break internally.

    post your results from the ohm test for the coils

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