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Solex Carb Theory, Tuning

Discussion in 'Early CJ5 and CJ6 Tech' started by GTS Dean, Feb 21, 2019.

  1. Oct 23, 2019
    GTS Dean

    GTS Dean New Member

    Texas
    Joined:
    Feb 21, 2019
    Messages:
    42
    7 months later update: (long)

    The Jeep was bought jointly by my 2 young adult sons. I was doing what I could as a gearhead dad, but ran out of motivation and time. They decided to take it to a great local ASE garage that does vintage cars and trucks for professional help before hunting season starts. I took the service manual by and gave him the rundown on what we had done. I was told by the boys he got it running better, but still had issues.

    So, I stopped by today to find out what he had determined. Turns out it had a large vacuum leak from the wiper/fuel pump/pcv hose being disconnected (likely due to my industrial pressure washer cleaning of the engine and undercarriage). The rough idle started right after this as I recall, but I never thought about it because the previous owner switched to electric wipers. I started chasing ignition issues instead. He said the reason #3 hole acted dead is because the metal vacuum tube attached to the manifold right next to the intake valve and was diluting the mixture! Once he plugged that, the motor purred beautifully.

    He then talked about the massive lean flat spot that I'd been fighting since the get-go. I've never worked on a Solex before and wasn't liking what I was dealing with, nor did the pro. He recommended to the boys that they replace it with a Carter he could understand, so they ordered one from Kaiser/Willys. When I got home today, it was on the front door step! I'm going to drop it by in the morning so he can get it installed and find out what else ails it. We are definitely going to install a complete new wiring harness from Walck's to correct decades of nightmares that made it a real problem for the previous owner to live with.

    Updates to follow...
     
    ITLKSEZ likes this.
  2. Oct 24, 2019
    Dave Deyton

    Dave Deyton Member

    Fuquay-Varina, NC
    Joined:
    Oct 12, 2003
    Messages:
    847
    I got a new Solex at a good price to use until I got the Carter rebuilt. Could not get the idle right. Sprayed WD40 around the base of the carb and the engine revved. Turned out all the screws in the carb were loose from the factory. A good tightening on the bench fixed the vacuum leaks and then I could get it adjusted to run correctly.

    Vacuum leaks can drive you crazy chasing phantoms.

    Dave
     
    Jrobz23 and 65CJ5 SRD like this.
  3. Oct 24, 2019
    65CJ5 SRD

    65CJ5 SRD Member

    NM
    Joined:
    Aug 12, 2019
    Messages:
    103
    My Solex was like that too (bolts loose) when I first got it. Had to tighten everything up.
     
  4. Oct 24, 2019
    ITLKSEZ

    ITLKSEZ Hope for the best, prepare for the worst

    Liberty Lake, WA
    Joined:
    Aug 13, 2015
    Messages:
    6,656
    20 years ago, I stacked washers behind the spring on the accelerator pump linkage to make it more of a direct action to get rid of a dead spot off idle. It’s been fine and untouched since.
     
  5. Oct 24, 2019
    Jrobz23

    Jrobz23 Member

    Northern, WI
    Joined:
    Oct 3, 2016
    Messages:
    942
    Similar situation to me. Mine didn't have loose port screws but the acc pump was effectively disabled from the factory with how loose it was. Full arm movement didn't impact the pump. After some fiddling with it, I was very happy with how my Solex ran.
     
  6. Oct 28, 2019
    GTS Dean

    GTS Dean New Member

    Texas
    Joined:
    Feb 21, 2019
    Messages:
    42
    Final update:
    The Carter is installed and the motor purrs just like it should! Now we can fix the minor exhaust leak under the floor and we'll be ready for action just in time for Opening Weekend!

    Next up: Electrical system!
     
    Glenn, Jrobz23 and jeepstar like this.
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