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32 DCOF Side draught question/issue

Discussion in 'Front-Engine Rear Drive Fiats' started by pdxgeo, Jun 14, 2017.

  1. pdxgeo

    pdxgeo True Classic

    I got the 1100R running but the carb is giving me fits. Ive adjusted the float 3 times, my measurements seem spot on 7-12 but of course I may be wrong. While the car is running there is no fuel leak but about 20-30 minutes after I shut it off I find this puddle in the secondary.

    Anyone have any experience with side draught webers? thoughts? thanks all!

  2. NM850

    NM850 True Classic

    Albuquerque NM
    You may have a leaking float. As the car sits the float sinks and opens the needle valve.
    Also that's not the secondary. The side draft is really like two single barrel carbs that share the float and throttle shaft.
  3. fiatfactory

    fiatfactory Steve Cecchele

    Western Australia
    DCOF comes with both brass and 'spansil' (nitrophyl) floats... brass float is easy to tell if it's leaking, shake it and you can hear fuel inside. Spansil floats are not hollow, but they do become fuel soaked and are then too heavy, displacing more fuel and giving all the symptoms of an incorrectly set float level. Rough test is to dig your thumbnail into the side, if it shows up a wet patch the float is fuel impregnated... true test is to weigh it... but off the top of my head I'm not sure what it's supposed to weigh. (I do have a Weber bible at home that will have the factory values if you have no luck searching for it) a gram or two will make all the difference.


  4. 128kid

    128kid Courtney Waters

    Charlotte, NC
    I can dig out my factory manual in the morning and see what it says on settings. I converted my 124 wagon to run a 32DCOF, but the carb was new from Pierce Manifolds so it ran ok straight out of the box. Its worth noting that the carb sits right over the exhaust manifold and has a tendency to heat soak after shutdown. My manifold did not come with a heat shield and I've always intended to make one. One of these days...
  5. 128kid

    128kid Courtney Waters

    Charlotte, NC
    This is from my 1968 124 factory shop manual. Not sure if it's any different on the 1100.

    IMAG2448.jpg IMAG2449.jpg IMAG2450.jpg IMAG2451.jpg IMAG2455.jpg
  6. GregS

    GregS ProjectX

    Not sure if the DCOF is the same, but my 40 DCOEs were leaking fuel very slowly when left for a while. Was mostly dripping from the pump jets, reseated the balls in the delivery valves and discharge valves by lightly tapping with a brass rod. Then noticed 2 auxiliary venturi nozzles weeping fuel slightly, even when the fuel level was below the nozzle/channel hole in the emulsion tube well, the only reason I could find was porous castings in the 40 year old carbies. I ended up making some thin wall brass tubes to fit the hole from the emulsion tube well to the auxiliary venturi feed in the carby throat, then loctited them in position with 290 wick in loctite. Seems to have cured the leaks.
  7. Dr. M

    Dr. M Low Mileage

    Idaho Falls
    One thing to check on the DCOF is the pressed-in venturi. The carb bores can get a little out of round and the venturis can get loose. Using a needle-nose pliers, grab the venturi and see if you can pull it straight out (be careful of the choke plates; these and the shaft have to come out if the venturis are loose). If it comes out, or wobbles a bit, this is your problem. The only solution I know is to get the venturi out, clean everything real well, then use crankshaft bearing shim stock to shim the blank side of the venturi. It only takes a few thousandths thick stock. I remember (now this is 40 years ago) snipping a feeler gauge down to try and measure the clearance. Once I got close, I cut a slightly thicker shim out of the shim stock that would just fit inside the slot for the venturi (the blank side, not the fuel side). Then, put the carb on the bench so the bores are pointing up, put the shim into position. I left the shim a little long so a tiny piece of masking tape could be used to help hold it in place. The I careful pushed the venturi into position, then tapped it into place using a piece of soft wood as a dowel and a hammer to carefully tap the venturi in. Make sure the shim does not slide and bunch up at the bottom. Once the venturi is secure, take a razor and cut off the excess shim stock. The repair will last the life of the carb. I've used this on other carbs like the Weber/Holley 3100 that came on the Chevy Vega. Seems all the diecast carbs warp over time. Back in high school, my sister had a red 1100R that she named Rubella (it had the Solex carb), and I had a '61 1200 Cabriolet that I transplanted the 1100R engine with a Weber, and the front disc brakes from the 1100R. I used to know every wrecking yard that had Fiat 1100/1200s in the Portland, Oregon area.

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