Help....Merc 20hp

Discussion in 'Bubba's Outboards' started by Quackshutr, May 24, 2009.

  1. Quackshutr

    Quackshutr New Member

    Messages:
    133
    State:
    Oklahoma, Collinsville
    Hey guys,
    I've got an early '70's 20 HP merc that has been a pretty good motor, the last trip out a few weeks ago it would only part of the time excellerate (sp?) when given full throttle, the rest of the time it would only go about 4mph, pretty much about 1/5 throttle or there abouts.
    This morning we went jug lining and it did that the entire morning,,,would never excellerate higher. I thought maybe there was a bleed hole or something clogged, took it home, cleaned the carb and couldn'd find anything wrong with it, ran fine at home. Went back out this evening to pick up my jugs and it would start and idle but when given the throttle it would kinda bog then die. I finally got it to run a little bit in reverse to get us back to the ramp, 100 yards away. In forward gear it would die every time.
    I've got a feeling it's the fuel pump but really don't have a clue.
    Anybody got a helping idea for me??
    First off I'm not going to be able to get a kit this weekend for the fuel pump and I've still got to pick up my jugs from the lake! !

    Thanks
    Q
     
  2. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    You need to do a compression check and spark test. Now did the motor shake real bad when you tried to bring the rpm's up or did it just sound like it was choking to death. Is your vent screw open on the fuel tank. Take the fuel line out of the inside of the fuel tank and see if it is bad or stopped up.. Check your fuel lines from tank to carbs before starting to throw parts at it. As for running your jugs better get a friend with a boat because if you keep running that one in that shape it is going to blow it up.
     

  3. Quackshutr

    Quackshutr New Member

    Messages:
    133
    State:
    Oklahoma, Collinsville
    Sounded like it was choking, bogging down like it's fighting for fuel, if you can get it past that spot it would rev up a little bit but not a whole lot.
    Vent is open on fuel tank. I've even ran it with out the tank fill cap, no change.
    I stayed up till 3am, took carb apart again and slowly made sure everything was clean. Put on new carb to engine mounting gasket. Put it in my handy dandy test tank this morning.........no change, did the same as before.
    Did notice that the fuel hose didn't get real firm when I pumped it up, priming it this morning.
    Spark test........just check and see if the plugs are firing? Pull a plug and leave it in the plug wire,,,pull the cord?

    Thank YOU!

    Q
     
  4. Quackshutr

    Quackshutr New Member

    Messages:
    133
    State:
    Oklahoma, Collinsville
    Used my tank on my bosses boat this morning with no problems. Guess I'll buy a new hose/bulb combo and see if that helps.

    Q
     
  5. Longjohn119

    Longjohn119 Well-Known Member

    Messages:
    1,201
    State:
    Iowa
    Does yours have the carb with the fuel pump integrated? If so you need to rebuild the fuel pump at the same time as the carb, there is also a screen/filter in the pump assembly that can clog
     
  6. recordbreakin1

    recordbreakin1 New Member

    Messages:
    746
    State:
    texas
    IT SOUNDS LIKE IT COULD BE YOU HOSE OR FUEL BULB.I HAD ONE DO THE SAME THING ON ME ONE TIME THE BULB WILL DRY ROTT AND SMALL PIECE WILL STOP THE FLOW OF FUEL.REMEMBER TO START WITH THE SMALLEST THINGS FIRST.
     
  7. Quackshutr

    Quackshutr New Member

    Messages:
    133
    State:
    Oklahoma, Collinsville
    LongJohn and Recordbreakin,,,,,,,,,,,,,thanks for the replies.
    Yes it has the integrated fuel pump, I'm looking at putting a kit in that,,,about$10 or so.
    The bulb and hose only has about 3 trips to lake on it but that is something else I'm looking at,,,probably first.

    Q
     
  8. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    If you used another tank and fuel line and it worked good then go get another tank and fuel line. Not that big of a deal money wise.