240z rpm & hitachi carburetors (su type) | The Z Club of Great Britain

240z rpm & hitachi carburetors (su type)

Discussion in 'S30 (240Z,260Z,280Z) General' started by datsunnyit, Jun 11, 2017.

  1. datsunnyit

    datsunnyit Forum User

  2. jonbills

    jonbills
    Z Club Member

    An air leak somewhere maybe.
     
  3. SacCyclone

    SacCyclone
    Z Club Member

    Check to see that both of the main jets on the SU's are pushed up completely with the choke off.

    Put a timing light on that engine and make sure your timing is not jumping around too.
     
  4. TimW

    TimW 1978 UK RHD 260z

    Carb Throttle Shaft wear maybe.
     
  5. Nigel Brook

    Nigel Brook New Forum User

    Certainly carb related. How old are your carbs?
     
  6. datsunnyit

    datsunnyit Forum User

    new carbs some various thousand km but is new from USA remanufactured company.
    always have this problem
     
  7. jonbills

    jonbills
    Z Club Member

    What happens if you unplug the vacuum advance from the distributor?
     
  8. Farmer42

    Farmer42
    Z Club Member

    If they were older carbs, I would have said to balance them using an air flow meter and then check the float level settings but not normally on rebuilt carbs.

    With new or remanufactured/refurbished ones, I would still suggest balancing and it may even be worth checking the floats and float valves as they can sometimes stick or be set incorrectly. You might even have a bit of dirt or metal in the bottom of the float chamber left over from the rebuild that could be blocking things.

    You might also want to contact the company that rebuilt them and ask if they set them up before they leave the workshop.
     

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