Engine troubleshooting...?

Discussion in '1960-1966' started by audioclass, Dec 10, 2007.

  1. audioclass

    audioclass Member

    Joined:
    Aug 3, 2006
    Messages:
    41
    So as some of you may remember, I dropped the ZZ4 into my 63 about a year ago. It had been running great, but has been out of commission for a while as my transmission was having some issues. The truck itself has been inactive for about 4 months. I do start the motor every 2 weeks or so and allow it to fast idle for 10-15 minutes, making sure its got plenty of oil pressure. I fixed the transmission issue this past weekend, and I took the truck out yesterday because its been so long and frankly I missed her. Drove great for about 10 minutes, plenty of power on acceleration, but it seems the motor is running a little rich as it will cut out for a split second when i first nail it before revving up again "normally." When it does this, it appears to have plenty of power, but I'm sure its running rich and needs a tune.

    Anyway, the problem is that after 10 minutes or so of driving, it started to sputter and choke during acceleration. The motor would not rev, and it gradually became worse until I was forced to pull off to a side street and park it. I let the motor sit for a couple seconds, pumped the gas once and started it back up. It appeared to run fine at this point, with plenty of power on acceleration and none of the lagging, sputtering, and dying I had experienced before. It drove this way for another 5 minutes before doing the SAME DAMN THING, loosing power, exhaust sputtering, with a gentle popping sound (not like deceleration popping) until it died again. What the hell..... So I waited again, pumped the gas, started her back up, and she drove fine for another 5 minutes. Repeat this process all the way home, must have happened another 4 times before i brought it into the driveway. The motor stayed at a consistent 180/200 degrees throughout this process, so it wasnt overheating, I had plenty of oil pressure and the fuel is fresh.

    Does this sound like possibly the motor is just sucking TOO much fuel, and its building up and flooding it? I haven't adjusted the carb as it came from GM. Air filter is clean and unrestricted. I just dont know whats going on and would love if I could fix it on my own without having to pay someone ELSE to do it. Any ideas?
     
  2. drabo

    drabo Member

    Joined:
    Jun 9, 2003
    Messages:
    759
    Location:
    Patrick AFB, Florida
    Try some staybil in the gas tank.
     
  3. audioclass

    audioclass Member

    Joined:
    Aug 3, 2006
    Messages:
    41
    Isn't that more for keeping gas from going bad? Its got a fresh tank of 93oct in it.
     
  4. drabo

    drabo Member

    Joined:
    Jun 9, 2003
    Messages:
    759
    Location:
    Patrick AFB, Florida
    Yes it is. But it might have built up a little condinsation sitting for a while. Try some cheap line drier to get rid of any possible water.
     
  5. audioclass

    audioclass Member

    Joined:
    Aug 3, 2006
    Messages:
    41
    I'll try that thanks!
     
  6. Oldcarsnbikes

    Oldcarsnbikes Member

    Joined:
    Nov 25, 2007
    Messages:
    51
    Location:
    50 Km near Frankfurt/M -GERMANY-
    Do you have manual or automatic choke (hot water opens the choke)?
     
  7. audioclass

    audioclass Member

    Joined:
    Aug 3, 2006
    Messages:
    41
    It's an electric choke, but as I recall it doesn't use hot water, unless it just measures the intake manifold temp. Its a Holly 4150 750cfm.
     
  8. Oldcarsnbikes

    Oldcarsnbikes Member

    Joined:
    Nov 25, 2007
    Messages:
    51
    Location:
    50 Km near Frankfurt/M -GERMANY-
    OK,did you check for a closed choke when the engine started not to run right?You could remove the air cleaner and hold the choke open with a fixture for a test drive and see if the problem still exists.Also it could be a electric fuel pump with the pressure set a little to high...:confused:
     
  9. audioclass

    audioclass Member

    Joined:
    Aug 3, 2006
    Messages:
    41
    I will definitely give that a try. We've had a lot of snow up here in NH over the past few weeks so I haven't had much time to be able to get out and work on it. I wasnt able to check the choke at the time, I was too busy trying to get home. Its a mechanical fuel pump, brand new, so I don't think thats the issue, but the choke definitely seems possible. Is it possible to retrofit a manual choke to a carb with an electrical unit? I wouldn't mind having the manual, but the motor came with an electric choke so I just stuck with it.
     

Share This Page