Weber’s hesitation mid range throttle help

[911mnypt]

I have just about exhausted my mechanical aptitude and need a little advice on my hesitation problem.
The scenario:
• Car starts easy with just two pumps and does its usual popping spiting thing for a few minutes.
• Warm Idle is smooth, no popping or spitting.
• If I do easy acceleration the car is smooth through all gears with no hesitation at all.
• If I mash the peddle down the car runs like a deer and is way too much fun! I actually ran in an autocross at Mather Field with no problems.
• I get the hesitation in the middle of the two when I try moderate acceleration. No popping or spitting, just hesitation.
My set up:
• Euro 3.0 motor with a redneck top end refresher last year
• Euro stock distributor that I just recently cleaned & serviced
• 74 heater exchangers with stock 2 in 1 out exhaust
• Weber 40 IDA
• Fuel pressure set @ 3.5 psi
• New fuel filters
• 34 main venturies
• 1.50 main jets (wondering if 1.60’s would help)
• 170 air correction jets
• 60 idle jets
• F26 emulsion tubes (thanks Steve)

[Steve@Rennsport]

JMHO,...150's are too lean (remember our oxygenated fuels).

Try 155's and see if that helps. I suspect you may need to fiddle with your accelerator pumps a bit.

[911mnypt]

Thanks Steve...I will put those emulsion tubes in the mail to you on Monday.

Does anyone have any 1.55 main jets that I can barrow for a test?

[Trackrash]

Bruce Anderson recommends F3 emulsion tubes and 160 main jets for an otherwise stock SC motor. F26 emulsions are lean at transition for smog motors and require an even larger main jet.

[911mnypt]

I had F3 tubes in and Steve loaned me some F26 which seemed to make the car run better...maybe the higher compression of the euro motor makes the difference? So many combinations to play with...