I have a 223 I-6 with the clifford performance setup which includes a Weber 38 DGAS. The engine idles great and drives pretty decent except for hesitation on take off. I have even had it stall on me once on take off. I have up sized the idle jets 2 sizes to (55) this was required to keep the engine running once the choke opened. I have no vacuum leaks and a new coil and a new set of points. My thought on this is it is the accelerator pump working too well causing the engine to bog down on take off. Is there any sort of accelerator pump adjustment on these carbs? I cant seem to find any info about it and this appears to be a common problem on other OT threads. I am going to check my vacuum advance set up for proper working order tonight and would like to try to adjust the accelerator to see if this could be the issue. Any help would be much appreciated!!
More likely the pump not working well enough.... it should have at least a 70 pump jet. The pump is operated by a cam on the end of the primary shaft and a lever which acts directly on the pump diaphragm.... no real adjustment.just make sure the lever is contacting the cam and it hasn't been bent or modified, and that the diaphragm is good and it has a return spring behind it.( Often in the wrong place or left out.) I would say if it's too rich your problem is more likely the power valve diaphragm , they get hard and brittle and keep the power valve open all the time. If it is starving check the accelerator pump diaphragm and the pump jet and pump delivery valve are all clean clear and operating. Pump and power valve diaphragms are the same parts as used in Holley 5200 and DGAV Webers fitted to Pinto 2.3 if you have problems finding parts. As are most of the jets etc.
Webers are very sensitive to dirt and bad adjustments... float level is critical. They are a much more sophisticated instrument than a lot of other carbs. If the 55 idles you have fitted are working and you can adjust from too rich to too lean with the adjustment screws they are probably OK but if they are only just enough to make it idle with the screws more than three turns out you will get a lean stumble on the transition from idle to intermediate circuits. If the emulsion tubes are blocked in any way you will also have problems there. One common fault is for people to put the small air corrector jet from a progressive carb into the secondary side of a DGAS . DGAS is not progressive so be sure someone hasn't replaced one of the air correctors with a smaller jet . All jetting should be the same both sides of a DGAS. Stock they had 145 mains and 185 airs with 45 idles, 70 pumps and F50 emulsion tubes..... but as I said people put parts from DGAVs ( Pinto carbs) into them and make a dogs breakfast of the carb .
I knew someone on here would be able to help me out! A month back I had to replace the accelerator pump diaphragm because it was leaking and cracked. This is a new carb that so far doesnt seem hogged together from other carbs. I will check the power pump diaphram. I might just be a complete idiot and jumping to conclusions. I turned the screws out 1 turn from seating and it was still running well while before it was 2 1/4 turns out. I'll spend more time tuning and adjusting maybe it seemed to be a lean condition when it was actually rich. I'm confused now! Thanks for all the great info!
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