Boats & Blinds Forum Sponsors

Mercury 50HP 2 stroke issue

Discussion in 'Boats, Blinds, & Gadgets Forum' started by RTIC, Jul 5, 2018.

  1. RTIC

    RTIC Senior Refuge Member

    Messages:
    286
    Joined:
    Mar 23, 2017
    Location:
    NW Ohio
    I could use some advice or direction to the below problem.

    My pontoon has a 2001 50 hp 2 stroke mercury on it. I used it on the 4th with no issues ran great. Jumped on it this morning to go for a cruise and it would just crank over like there was no fuel or spark. During the use on the 4th i did mix in sea foam to the 12 gallon tank. I used about 7 gallons of fuel that day.
    This is what ive done to it so far:

    1. new fuel line and primer bulb
    2. new spark plugs
    3. installed a temp tank and fuel line

    The above didnt change a thing.

    I then cranked the motor over and threw it in gear quick. That would allow it to fire up but not to idle.
    After that I could put the lever in high idle and it would start but run terrible. I back it down to just above neutral idle and it would run but sputter. I then put it in neutral to idle and it would spit sputter and shut down after about 3 minutes.Unfortunately the boat is still in the water and the layout doesnt allow me great access to the motor (overhead only).

    My question is does anyone know something else I should check before pulling it out of the water? My thinking is the fuel filter under the cowl could be partially clogged or maybe the fuel pump is going out but im no outboard mechanic.

    I did install a temp tank with new fuel to rule out the fuel tank and lines after i was able to fire it up. It gave the same results as above though.

    Thanks for everyones assistance.
     
  2. Phytoplankton

    Phytoplankton Elite Refuge Member

    Messages:
    3,015
    Joined:
    Jun 26, 2008
    Location:
    CA
    Definitely check the fuel filter. Do you have a good strong (blue not orange) spark? Might of sucked up some crud into the carbs(s) or maybe a stuck float. Really hard to diagnose when you're not actually there to see/hear it run. Try pumping the bulb while it's running, if no difference that could rule out a bad fuel pump. Also, try tapping the carb with the handle of a screwdriver above the bowl, if the float is stuck sometimes that will free it up. Hope this helps, but a trip to the mechanic might be in order.
     
  3. calling4life

    calling4life Elite Refuge Member

    Messages:
    1,550
    Joined:
    Feb 10, 2009
    Location:
    Minnesota
    100000% torque the headbolts properly, just do this, most people don't know that you're actually supposed to do it about every 100hrs

    My motor did this, I took it to a shop that said the motor was now junk

    I called the guy that sold it to me, he arranged a meet with me, said he had a great idea what it was. I get to the parking lot, he pulls the motor out of my truck, pulls it a little, says, yep, head bolts, tightens the head bolts right there, says pull it now, night and day...

    We took it back to his cabin and he replaced the $17 head gasket anyway, ran perfect.

    $17 head gasket and tighten head bolts properly vs. shop that said it was junk....

    He has worked on motors and been around the industry for years, says it isn't uncommon for shops to do something like that, the owners usually just leave the motors instead of paying their bill, then the shop fixes them cheap and sells them to make some great, easy money.

    I just checked my head bolts after Wednesdays operating of the boat and they were a little loose

    So check those properly, and torque them in the right order...
     
  4. perfmarine

    perfmarine Elite Refuge Member

    Messages:
    1,041
    Joined:
    Feb 3, 2012
    Location:
    Atlantic


    50 merc 2 stroke don't have headbolts!!!
     
  5. perfmarine

    perfmarine Elite Refuge Member

    Messages:
    1,041
    Joined:
    Feb 3, 2012
    Location:
    Atlantic
    You may have clogged the carbs with the sea foam, broke some crud in the carb loose and plugged up some jets.

    Or you have a spark issue.

    Check your fuel for water. Pump some into a jar and see if it is clear, if it's cloudy at all you have water.
     
  6. calling4life

    calling4life Elite Refuge Member

    Messages:
    1,550
    Joined:
    Feb 10, 2009
    Location:
    Minnesota
    That's odd that they do that, a shame, sounded exactly like what my motor did and it's an easy fix. Good luck
     
  7. FLATBTM

    FLATBTM Refuge Member

    Messages:
    42
    Joined:
    May 9, 2018
    Location:
    Alabama
    As with every single outboard engine, you need to check the compression before lifting a single wrench. Then check your spark. Then check fuel.

    If spark is good then check fuel first by pumping bulb while running. Note any change. Also, while running with the cowl and airbox cover off you can hit the carb throats with a timing light to check for broken reed petals. If none of that changes anything, you need to removed the carbs and go through them.
     
  8. RTIC

    RTIC Senior Refuge Member

    Messages:
    286
    Joined:
    Mar 23, 2017
    Location:
    NW Ohio
    Looks like im going to change out the fuel filter under the cowl and check the fuel lines to the fuel pump first. It seems the most logical to finish off the fuel system. My local marina is helping me trouble shoot it piece by piece before i need to bring it in to them.
    I most likely will be switching motors later this week with a bigger motor though and just work on it as i get time so i can get back to enjoying the water.
     
  9. callinfowl

    callinfowl Kalifornia Forum

    Messages:
    25,107
    Joined:
    Aug 15, 2004
    Location:
    NORKAL
    Take the air box off start the motor any way you can, while running it at half to full throttle have a friend cover the carbs to choke out the engine. Doing so may create enough vacuum to pull tiny peices on junk that may be stuck in your carbs. It's worth a try at this point and may save you a trip to the boat Doc.
     
  10. RTIC

    RTIC Senior Refuge Member

    Messages:
    286
    Joined:
    Mar 23, 2017
    Location:
    NW Ohio
    New development.
    Sunday i was getting it ready to pull out of the water and decided i was gonna see if i could take it a for a quick ride. My neighbor had his boat on standby in case i needed a tow.
    I come of of the dock and it idled terrible out. Hit the open water, opened the throttle all the way and it ran perfectly. I would say probably the smoothest it has ever ran. Come back to dock at idle speed and it was rough with some spitting and sputtering. I also noticed at idle sitting in the dock the motor isnt pushing much water out. Could this be a contributor to my issues?
    I still pulled the boat and brought it home to change motors it just surprised me at how well it ran on the open water.
     

Share This Page