Set Up That Two Needle Carb!

Main Needle

  • STEP 1 – Fill the tank to at least one third full
  • STEP 2 – Open the throttle fully and close main needle completely
  • STEP 3 – Open needle three whole turns from closed
  • STEP 4 – Place a finger over intake and with a gloved hand rotate propeller 6 times
  • STEP 5 – Remove finger and close throttle to one third open
  • STEP 6 – Connect glow plug battery
  • STEP 7 – Start engine – either by hand or starter motor
  • STEP 8 – Remove glow clip (with care)
  • STEP 9 – Gently (very important) open throttle to flat out setting
  • STEP 10 – Hold nose of model up at 60 degrees or so, keeping clear of propeller arc
  • STEP 11 – Close main needle inward SLOWLY until engine rpm’s peak out to a crisp two-stroke
  • STEP 12 – Open needle one or two clicks out from absolute rpm

Idle Needle

  • STEP 1 – Close throttle to one quarter (i.e. fast idle)
  • STEP 2 – OPEN secondary needle to one quarter turn
  • STEP 3 – WAIT for 5 seconds and observe results
  • STEP 4 – If idle slows close needle back to where it was
  • STEP 5 – CLOSE needle one quarter turn
  • STEP 6 – WAIT for 5 seconds and observe results
  • STEP 7 – If idle speeds up then you are turning in the right direction – opening or closing the needle until idle speed peaks is your goal
  • STEP 8 – Open engine throttle wide and check for crisp response
  • STEP 9 – If the engine hesitates open secondary needle by a click or two
  • STEP 10 -If engine splutters and throws fuel droplets from the intake close secondary needle by a click or two
  • FINALLY Open throttle wide and recheck main needle setting with nose raised


  • DO Make sure your plumbing isn’t leaking with no bubbles in the fuel line
  • DO Mount fuel tank securely in foam supports
  • DO All FULL POWER adjustments with nose of model held at 60 degrees nose up
  • DO Set up engine with at least one third tank of fuel


  • DO NOT TOUCH THE MAIN NEEDLE SETTING OTHER THAN WHEN COMPLETELY ON FULL THROTTLE (i.e when the carb barrel is fully open) – this is the most common mistake !
  • DO NOT Make engine adjustments with the glow clip connected
  • DO NOT Make adjustments with the propeller arc either in line with your body or and up to 10 degrees either side (propeller blades moulded at an angle – and therefore fly off at an angle !!!!)
  • DO NOT Assume if a glow plug glows or is new that it must be OK – it could well be faulty – if the element looks grey or distorted, throw it away and treat your motor to a new one !
  • DO NOT Leave fuel in your fuel tank between flying sessions
  • DO NOT Make adjustments from flight to flight (the second most common mistake)