whoya

iTrader: (1)

I finally swapped carbs after changing everything out in the ignition trying to find a miss.
My Holley 850 Double Pumper causes a slight constant miss when running in the 3800-5000 rpm range.
What would cause a miss in that range? To much fuel dumping in some how?
Fuel pressure was set right and levels to.

ezstriper

you could be on the edge of the power valve opening, lean at that point then opens and you are good, what power valve are you running ? should be a 6.5 but that can change due to cam, intake, etc...are you running a vacume gauge ? they are very handy....

whoya

iTrader: (1)

I tried a 6.5 and a 5.5 with same results. Im showing a vacuum between 10-14 it would not stay steady at idle.

fbc25el

Do you know what your fuel pressure is in that rpm range?

whoya

iTrader: (1)

I have a gauge at the carb and put another one on (to check while running)with a line and its holding fuel pressure in that rpm range. I tried between 6 1/2 to 7/ 1/2PSI no difference.

Im about to go buy another Carb.

Tow-N-One

is the motor supercharged, if so you need a boost refrence carb

whoya

iTrader: (1)

No, its a N/A 547CI

ezstriper

547 ci ? thats really taxing a 850, call patrick @ pro systems carbs, he set you strait !!! off the shelf carbs may not work well...Rob