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63 F-head Sputtering And Dying

Discussion in 'Early CJ5 and CJ6 Tech' started by joshs1ofakindxj, May 29, 2016.

  1. joshs1ofakindxj

    joshs1ofakindxj CJ5 Owner

    63 CJ5, all stock F-head 4 cylinder. Carb rebuilt last summer as well as new points, condensor, plugs, wires, cap rotor. It's driven for a day every other week when it's nice in PA (so like 6 months) and it plows snow as needed in the winter. Fuel is treated with stabil before sitting.

    Last Friday it was a sunny warm morning so I drove 20 miles to work without issue. At lunch time, it had warmed up to 78ish and I took the jeep to lunch. I noticed it was missing a little in the lower RPMs but it made it to lunch and back. When I went to leave work at 4pm it was missing worse in the lower RPMs and as I limped home it got worse to the point I was barely making it up hills as it was sputting and making no power, unless I got into the highest RPMs where it seemed to run fine.

    At one point when I stopped to top off the fuel tank, thinking water in the fuel might be the culprit, I looked under the hood and observed bubbles coming into the glass top of the fuel pump from the tank and I found that the metal elbow for the vacuum line on the fuel pump closest to the fender had fallen out of the pump.

    I made it home and a few days later I put a bottle of dry gas in, fixed that loose vacuum line on the pump, and checked the point gap. The jeep seemed to be running fine so I drove it again yesterday on an even warmer day. I had no isues going 20 miles, but when I left I was running poorly again, and it was even worse and I had to stop and have a friend get me with his trailer.

    The jeep will start, idle nicely for a moment, then start to miss, and if I try to rev it up it puts up a fight with more missing and sputtering. It won't even get to the higher RPMs and rev cleanly like it would before.

    What should I attack next? My friend says coil, as it very well may be original.
     
  2. chris423

    chris423 Sponsor

    Coil and check the gas line for trash maybe . there is a way to check the coil with a meter check it when it is cold and hot .
     
  3. scoutpilot

    scoutpilot Member

    Sounds like the condenser has gone bad. This happens more often than most care to think about.
     
    jasonjp62 likes this.
  4. PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Could be the condensor... although I've never had one fail.

    Good you checked the point gap - but did you clean the points? (Fine sandpaper, then also wipe clean with a business card.)

    I would remove the fuel line at the pump and back-blow it out until you hear bubbles in the tank - the in-tank filter may be clogging.

    Also I'd check carefully for vacuum leaks, including the PCV and wiper tubing etc.

    Water in the carb? I'm not sure dry-gas does much these days, because the fuel is full of ethanol in any case. I have often found SeaFoam helps a lot better and gets the ethanol/water/crud out.
     
  5. Glenn

    Glenn Kinda grumpy old man Staff Member

    I've had condensers just die on me, and a coil decide to go bad but it was nice enough to let me get home by continually pulling over, cooling down....repeat process for a few miles. Obviously they don't all act the same way exactly but I'd put money on the coil or condenser one.
     
  6. joshs1ofakindxj

    joshs1ofakindxj CJ5 Owner

    Thanks everyone! I ordered a coil and condensor and will blow out the fuel line from the pump to the tank. Hopefully one of those does it!
     
  7. Glenn

    Glenn Kinda grumpy old man Staff Member

    I know breaking down isn't fun, but if you can get away with it replacing one thing at a time is best. Replace 2 things and you still don't know which fixed it.
     
  8. When you blow out the fuel line to the tank make sure you remove the tank cap first so you don't mess up your tank
     
  9. joshs1ofakindxj

    joshs1ofakindxj CJ5 Owner

    I just swapped in a new coil and it won't run at all now. Starts and craps out right away. The new coil says must use with external resistor. The old one doesn't say that, so I'm guessing I bought the wrong thing. Is it possible I damaged anything?
     
  10. Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

    Yes wrong coil but it will run along time like that, after a whuile it may burn out your points but a few minutes (or hours) won't hurt anything.

    Did you replace the condenser yet?

    H.
     
  11. joshs1ofakindxj

    joshs1ofakindxj CJ5 Owner

    No, sadly. I've been playing games with rockauto. They sent me one, it was wrong, they sent me another, it was wrong again, they refunded me because of their inventory error so I just placed an order for a condensor of a different brand. Usually I never have issues with them, and luckily I'm not in a hurry I would of walked into a store and bought one. It' a cheap part, but I'm always ordering parts for multiple vehicles so I just toss it on an order.
     
  12. joshs1ofakindxj

    joshs1ofakindxj CJ5 Owner

    Right now though, I'm going to go to the store and get a coil, because I want to at least rule out one item today!
     
  13. joshs1ofakindxj

    joshs1ofakindxj CJ5 Owner

    Luckily the guy at Napa knew what I needed because their computer tried to give me a 6V coil. He poked around and found a 12V coil with internal resistor.I put it in and it made no difference. I also back flushed the fuel line and it made no difference. Next is that condensor.
     
  14. joshs1ofakindxj

    joshs1ofakindxj CJ5 Owner

    It's not much of a video, but it shows the missing I hear at the tailpipe that is consistent, and some of the noises from the motor trying to run. I need to get a better video. It almost seems like it's hunting but the surging isn't consistent. I could still floor it to make it hesitantly rev to the moon and drive into the garage but it keeps wanting to die completely.

    http://vid3.photobucket.com/albums/y96/luvherinmyjeep32/IMG_3702_zpsjwre4eh6.mp4
     
  15. scoutpilot

    scoutpilot Member

    Metering rod adjustment.
     
  16. joshs1ofakindxj

    joshs1ofakindxj CJ5 Owner

  17. Glenn

    Glenn Kinda grumpy old man Staff Member

    Appears to be correct. Just follow it for whichever you have.
     
  18. joshs1ofakindxj

    joshs1ofakindxj CJ5 Owner

    I have the carb off now. The metering rod appears to be set up properly, with the tab bent right, but I don't have total confidence in my understanding of those instructions. Are there any other resources on how to do this adjustment, or how to rebuild this particular carb.

    Carb is a YF 938 SD. Does anyone recommend a certain rebuild kit?

    Is this one acceptable: Carter 1 Barrel YF Carburetor Kit 1932 - 67 AMC Chevy GMC IHC Jeep Kaiser Nash
     
    Last edited: Jul 19, 2016
  19. Glenn

    Glenn Kinda grumpy old man Staff Member

    You don't want a generic kit, too many variables. I think our member Scoutpilot sells kits.
     
  20. joshs1ofakindxj

    joshs1ofakindxj CJ5 Owner