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I converted my 83 Spider from FI to dual Weber DCOE carbs. Below are my carb settings but having a tuning issue. WOT is around 12.2 - 13 on the AFR. Idle (900 RPM) is around 11 - 12 on the AFR. The problem is as soon as I give it a little gas, it seems to go rich and stumble for a split second. Any suggestions on my jetting to fix that issue? Also cruising at 2.5K rpm is very good in 4th gear. My car also has 10:1 Motronic pistons 12mm intake and 11mm exhaust cams.
1. Modified Choke Tubes: 33.5mm
2. Main Jets: 135
3. Air Corrector Jets: 190
4. Emulsion Tubes: F-16
5. Idle Jets: 55 F8
6. Pump Jets: 40
7. Accelerator Jets: .40
 

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What is the complete model number of the Webers? Jetting depends upon the type that you have.
 

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Richard Jemison
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Well the 55 F8 idle jets solved the stumble between 2500-3000 RPMs, as it was too lean there. About the only thing to suggest is to go to a smaller bleed back in the pump jets (two in the bottom of the float bowl). Try a pair of 20s. This "should" speed up the spray response from the accelerator pump. It will make the AFRs richer when ever the pump is being moved/depressed.
 

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If it is too rich when you give it a little gas then 35 pump jets and/or 60 bleed backs may help. Those are the "stock" sizes.
 
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