76 40hp Evinrude

Discussion in 'Bubba's Outboards' started by nkccatman, Jul 24, 2007.

  1. nkccatman

    nkccatman New Member

    Messages:
    46
    State:
    mo
    Just rebuilt carb,motor runs good at idle and low speed but cant get any high speed and boat to plane out!Checked linkage and it appears to be getting full throtle!Is there a high speed adjustment to check?It wouldnt reach high speed before carb was rebuilt either if this helps any!Any help would be gratfull!Thanks
     
  2. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    Wade have you done a compression check and a spark test yet. It may be running on one cylinder. what kind of plugs do you have in it. I would use champion plugs QL77JC4 and gap them at 35 or at 40 if you run in a slow trolling mode a lot.
    Take all your ground wires at the coils and clean them real well and check coils for cracks. That means removing them because the coils could be cracked underneath them
     

  3. Arkie55

    Arkie55 New Member

    Messages:
    669
    State:
    Mississippi
    I'm far from an expert and Bubba and Bob Paul know a lot more on this subject that I do. I'm only speaking form my own personal experience with carb rebuilding. Two years ago, I rebuilt the carb on my 1979 Evinrude 35 hp outboard. Like you, mine was running great at WOT but started missing and spitting and sputtering at all thorttle ranges. The usual tune up didn't help and the issue only got worse. I completed a compression check and spark test and found all was good. Next step was a carb cleaning and rebuilding. This is a simple task or at least should be. I removed the carb, disassembled and cleaned. I installed the carb kit and put the carb back on the engine. I hooked up the muffs and started that puppy up. She ran as smooth as silk. A quick trip to the local lake for a test run and that's when my confusion set in. :confused2: She wouldn't run much above a fast idle. I must have removed and installed that carb a half dozen times over the next two or three weeks. I though I had a port plugged somewhere. In chat one night I was talking to Jesse168 and mentioned my issue with the outboard. He started asking me questions about my rebuild and low and behold I had left out a seal (gasket) that seals the air space between pick up tube and the bowl of the carb. I had kept the carb kit and the seal was still in the package. The next morning I removed the carb once again, installed the little round gasket with the star shape flaps around the pick up tube housing and my problem was solved. Long story short, everything in a carb rebuild kit should be used during the rebuild. If you have anything left over, something was left out or not replaced. Check for that seal. You'll be glad you did.:wink: