How to remove carbs on GT4 | FerrariChat
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How to remove carbs on GT4

Discussion in 'Technical Q&A' started by marankie, Mar 10, 2008.

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  1. marankie

    marankie Formula Junior

    Aug 30, 2004
    252
    Agoura Hills, Calif
    Full Name:
    Martin
    #1 marankie, Mar 10, 2008
    I am trying to remove my carburetors on my GT4 to rebuild them. The spark plugs on #1 and #2 are very wet. I have bought rebuild kits from Pierce manifolds but at this time I cannot unbolt the carbs from the manifold.
    There are 4 studs and 13mm nuts holding the carb onto the manifold, but there is one right under the accelerator pump that I cannot get to. What kind of wrench will get to this. Especially on the #1 and 2 carb the warmup throttle stop is also in the way. Do I have to drain the cooling water, and remove the warmup throttle stop before I can remove the carb?

    How do you determine if the accelerator pump diaphragm is OK? If there are no visible leaks on the outside of the carb, and the 2 accelerator jets squirt OK into the carb bore, does this mean they are OK or is there a way for gas to leak into directly into the carb bore thus flooding the motor? If the accelerator diaphragm is OK there may not be a reason to remove the carbs from the manifold, which right now looks to be a very onerous task.

    How many guys feel it is needed to change out the butterfly shaft bearings and seals. I have new sealed bearings, but first the carbs have to be removed from the manifold (see above).

    Please chime in with your experiences.
    Thanks in advance,
    Martin
     
  2. gerritv

    gerritv Formula 3

    Jun 18, 2001
    1,400
    St Catharines
    Full Name:
    Gerrit
    #2 gerritv, Mar 10, 2008
    Hi
    You need to get a spare 13mm wrench and cut it short to get some of the nuts off. Once loose you can use gloved fingers to spin them off the rest of the way.

    My GT4 doesn't have the warmup gadget, so can't tell you if it needs to go or not.

    Re the butterflies, the risk is in bending the shaft to remove the nuts and butterflies. When re-installing the butterflies you need to stake the screws that hold them, again without a jig this risks bending the shafts. Superformance.co.uk has the butterfly screws, never looked elsewhere (e.g Ricambi didn't exist at the time). In the end I didn't replace my shaft bearings, but I might this time.
    The pump diaphram I replaced, not sure how I would check it. It was included in the kits I bought.

    Gerrit
    http://dino308gt4.com
     
  3. yelcab

    yelcab F1 World Champ
    Consultant

    Nov 29, 2001
    13,662
    San Carlos, CA
    Full Name:
    Mitchell Le
    #3 yelcab, Mar 11, 2008
    +1 on what Gerrit said.

    You can get to all four nuts, just need stubby wrenches, at sometimes at an angle.
    Unless you feel the need to really replace the butterfly nuts, screws, and bearings, I would just leave them be.

    Have fun.
     
  4. Corsa308

    Corsa308 Formula Junior

    Apr 22, 2007
    290
    Sydney, Australia
    Full Name:
    Steve D
    #4 Corsa308, Mar 11, 2008
    Same here, I just cut down a spanner to suit.
    Re the accel pump, just do it anyway so you know all is freshened up.
    I didn't do my bearings as they seemed AOK at the time.

    Steve
     
  5. Beta Scorpion

    Beta Scorpion Formula 3

    Jun 22, 2006
    1,379
    #5 Beta Scorpion, Mar 11, 2008
    Agree with all. I used a 'stubby' wrench, a 'crow foot' wrench and a 'cut off' Japanese wrench. The order you take them off can make it easier to get the next one off. Looking at the engine from the back, I did back left, then front left, then front right, then back right. Depending on the wrenches you have available, a different order may work better.
     

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