Who's ready for round 2?

Discussion in 'Bubba's Outboards' started by Matt Smith, Apr 22, 2006.

  1. Matt Smith

    Matt Smith New Member

    Messages:
    119
    State:
    Tennessee
    I replaced everything from the tank to the carb with the exception of the fuel pump. I DID install a new fuel pump kit (gaskets and whatnot). I also did the carb rebuild thing. The fuel pump does pump fuel, but evidently it's still not enough to keep the bowl filled at full throttle. Once I get to about 3/4 throttle, the motor starts surging. If I squeeze the bulb, the surging stops and the motor runs fine.

    Will a brand new fuel pump fix the problem, or have I overlooked something? Bear in mind that every fuel line has been replaced with 3/8 line except from the pump to the carb. Those fittings required a new 5/16 line. Also, every fitting has been replaced.

    Motor is a 1980 Evinrude 25.
     
  2. Bobpaul

    Bobpaul New Member

    Messages:
    3,039
    State:
    Supply NC
    You've got a fuel flow restriction somewhere.

    Were you accurate in setting your float position in the carb?
    Did you set the low speed adjustment correctly? In gear on the water with no restraints to the boat at idle speed.

    I've also seen the plastic pick up tubes in new tanks, suck themselves to the bottom of the tank. That would cause your bulb to collapse though.
     

  3. trnsmsn

    trnsmsn New Member

    Messages:
    1,214
    State:
    Missouri Originally Now I
    I'm With Bob Paul On The float Level Being Too Low, Double Check It.

    Have A Good Day & Good Luck, Elliot
     
  4. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    If you bought a new tank the the culprit is most likely the pick up tube in the tank either sucking to the bottom or not large enough to let the fuel thru.
     
  5. zappaf19

    zappaf19 New Member

    Messages:
    1,574
    State:
    Monticello,IN
    I had dirt in one of my carbs and it would do the samething. When checking the levels look in the bottom of the carb bowl. See whats in there if anything.
    Bill
     
  6. Matt Smith

    Matt Smith New Member

    Messages:
    119
    State:
    Tennessee
    I don't know if I did the low speed adjustment correctly. The motor has a decal that says low speed adjustment is 3/4 turn open. I turned the screw until in seated and opened it 3/4 turn. This was done in gear with no restraints, on the water, at idle speed.

    As for the float, it sat level when I installed it. See diagram A in my attachments below.
     

    Attached Files:

  7. Matt Smith

    Matt Smith New Member

    Messages:
    119
    State:
    Tennessee
    I forgot to mention that the primer bulb doesn't go flat at all.
     
  8. Matt Smith

    Matt Smith New Member

    Messages:
    119
    State:
    Tennessee
    I checked the pickup tube in the tank. It's 1/2 inch plastic cut 45 degrees on the end supposedly to prevent it from sucking to the bottom of the tank. It does not have a screen on the end.

    The tank is a Tempo brand 6.5 gallon model.
     
  9. Bobpaul

    Bobpaul New Member

    Messages:
    3,039
    State:
    Supply NC
    I'll get back with you tomorrow on the measurement for the float drop.
     
  10. Matt Smith

    Matt Smith New Member

    Messages:
    119
    State:
    Tennessee
    Thanks BobPaul. Incidentally, my fuel pump kit came with two round gaskets that have five spokes radiating out from the center. My original pump used one, so I only put one new gasket on. Why do they include two of those gaskets?
     

    Attached Files:

  11. Matt Smith

    Matt Smith New Member

    Messages:
    119
    State:
    Tennessee
    Come on now. This thread isn't ready to die yet!
     
  12. BigB

    BigB New Member

    Messages:
    125
    State:
    Van Buren, Arkansas
    Matt, i had a 40 hp yamaha do the same thing. the problem was a cracked o-ring on the fuel line where it connected to the tank. when i give it gas it would suck in air. took me awhile to find because it ran so good below half throttle. i did like you replaced lines cleaned & adjusted carbs. i'm no mechanic but maybe this will help good luck
     
  13. peewee williams

    peewee williams New Member

    Messages:
    3,111
    State:
    Pembroke,Georgia
    I had a mid 70s model 25 Evinrude.I had a few off the wall weird problems with it.I had the Inner lining of the gas line deteriorate,come loose and act like a check,or flapper valve.Only found this after replacing one thing at a time,and then splitting the old hose to look at the inside,when it worked.Also a hairline crack in a or bad coil.It would run good slow,run bad fast.I noticed visual deterioration of the coil.I changed it and it ran fine.I went ahead and changed both.Good motor.Ran well until it was stolen.Good luck,peewee-williams.