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  1. #1

    Default motor wont stay running

    hi. i recently purchased my first boat. its a 14ft aluminum with a 1975 20hp merc 200. the motor ran awesome here at the house. a couple of weeks ago i took it to the lake to try it out and i started having problems. first off, it had trouble starting. then when i got it started, it wouldnt stay running. it only runs for a few seconds after i prime it. so obviously its a fuel issue. i bought a new fuel pump diaphragm for it and that didnt fix it. im thinking something may be plugged in the carburetor maybe? i have a clymers manual and im thinking i may just disassemble it and clean every little orrifice. any other ideas? thank you

  2. #2
    Join Date
    Sep 2010
    Location
    ontario
    Posts
    11,983

    Default Re: motor wont stay running

    Clean carburetor , likely dirt in it.

  3. #3

    Default Re: motor wont stay running

    well, i disassembled the carb and cleaned it. it seems like that may have done the trick. i also cleaned the passage in the engine that lets the crankcase vacuum get to the fuel pump. it runs like a champ now. only problem now is sometimes it doesnt want to spit water from the pee hole. i plan on replacing the impeller anyway since i dont know when it was done last. i think i got a pretty good deal on this boat for $600 with trailer, motor, current registration, fish finder, and all the extras (anchor, oars, etc)
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  4. #4
    Join Date
    Aug 2006
    Location
    SW Ohio, USA
    Posts
    10,395

    Default Re: motor wont stay running

    i think i got a pretty good deal...
    you bet...enjoy but replace the impeller and thermostat if equipped.
    Fix minor things (replace wear items for preventative maintenance.) that cause major problems before they break.

  5. #5
    Join Date
    Sep 2010
    Location
    ontario
    Posts
    11,983

    Default Re: motor wont stay running

    No need to look for a thermostat , it did not come with one.

  6. #6
    Join Date
    Sep 2003
    Location
    New Tripoli, PA, USA!
    Posts
    14,307

    Default Re: motor wont stay running

    Whoa! Don't got off on a tandem until you read this:

    That motor (and Merc 110s--9.8hp) are notorious for plugged Tell Tales--the dopey angled fitting in the lower cowling plugs up very easily. My usual solution is to blow compressed air back wards as the motor runs (hard to do 'out there'). A wire can be used to poke te hole out, but if you want to eliminate it completely do this:

    Remove the plastic fitting and throw it away, then lengthen the hose and poke it out the bottom of the cowling (with a tie wrap to keep it out there). Problem solved, permanently.

    Jeff

  7. #7
    Join Date
    Sep 2010
    Location
    ontario
    Posts
    11,983

    Default Re: motor wont stay running

    Old impellers are subject to " sudden failure " and if it does you will destroy a fine motor.----------Replace it if you do not know how long it has been in there !!

  8. #8

    Default Re: motor wont stay running

    i replaced the impeller. it has waaay better water flow now

    Click image for larger version. 

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  9. #9
    Join Date
    Sep 2003
    Location
    New Tripoli, PA, USA!
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    Default Re: motor wont stay running

    Good deal. But don't panic if the Tell Tale suddenly stops working; the Tell Tale on those motors regularly plug up and need poking out.

    Jeff

  10. #10
    Join Date
    Sep 2003
    Location
    New Tripoli, PA, USA!
    Posts
    14,307

    Default Re: motor wont stay running

    ..."Allways top the gear oil off before every"

    Why? You think the thing will lock up if there's a tablespoon of oil missing! They can run 50% empty without a hint of trouble.

    Jeff

  11. #11
    Join Date
    Sep 2003
    Location
    New Tripoli, PA, USA!
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    Default Re: motor wont stay running

    ..."Hummm what service manual says to run it until it gets half empty of gear oil,.."

    Never said that, but the LU will operate just fine a 50 % oil capacity.

    .."if you keep it topped of the upper bearing and seal will last alot longer."

    I doubt it. At even 500 rpms the oil is flying all over the place in there.

    Jeff

  12. #12
    Join Date
    Sep 2003
    Location
    New Tripoli, PA, USA!
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    Default Re: motor wont stay running

    There's a misconception on oil levels caused by a lack of a dip stick to check oil levels. LAcking said device, the only safe way to determine the level is to fill it to the top. That way it's got plenty of oil, agreed?

    In the industrial world of gearboxes, there is a sight gage to determine proper oil levels, which is close to 50 %. This level reduces the tendency of the oil to aerate, which lowers its viscosity (and lubricating ability). Note the car engines are never run full of oil for the same reason. Also note the warning usually placed on the dip stick not to "overfill".

    Jeff

  13. #13
    Join Date
    Sep 2010
    Location
    ontario
    Posts
    11,983

    Default Re: motor wont stay running

    Always make sure outboard gearbox is full to the top, running them any other way risks disaster.---------The upper thrust bearing will fail , with motor coming to a " dynamic halt "

  14. #14
    Join Date
    Sep 2003
    Location
    New Tripoli, PA, USA!
    Posts
    14,307

    Default Re: motor wont stay running

    ..."The upper thrust bearing will fail "

    Not really.

    Jeff

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