I have dual dells that run flawlessly but have a stumble at roughly 55mph when you your foot into it up to 65ish it hits a very short lived stumble then instantly recovers, it almost feels like accel pumps need to feed more fuel to help the transition to the high speed jet, I'm just guessing... anybody that can throw me a place to start before I turn the wrong screw, its done it since I got the car, not a big deal but would like to tune it out. thanks Darrell
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I’m going through that now, too.
Reach around the carbs on the outside of the engine and at the very bottom of the carbs and in the very middle and just below the base you will find the accelerator pump actuator arms. They are adjusted with a 6mm nut on a threaded shaft. If the nut is screwed in you will get a sooner/larger accelerator pump squirt. Try turning that nut in about 1/2 turn on both carbs equally and see what happens. You can go as far as 1-1/2 turns but only increase in 1/2 turn increments. If that doesn’t cure it, you may have to return to the original accelerator pump stroke (remember how many 1/2 turns you have done) and then go to a smaller carb venturii. if it is now a 34mm venturii, then go to a 32mm to manage the airflow past the idle jet circuit to enrich it slightly along with the transition ports.
I will try it, I knew the accel pumps were there like our harleys, just didn't know what way to turn the nut to introduce more fuel, its going to rain today but will get back to ya after a test and tune day thurs. thanks Darrell
Turned the pump stroke adj. nut in 1 turn on both carbs and the stumble disappeared, the previous owner must have gotten used to it, the transition to the high speed side is seamless thanks for the advice Gordon.
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