Holley Guru's: I have a problem..

[Jefe]

I have a holley 650 vacume secondary 4 barrell on my daily driver 350. Mild cam performer intake, Mallory HEI, truck 4spd tranny..nothing crazy. When I give it gas it lurches or bogs down a little before it picks up and goes; or if I mash down the accelerator a little quicker than normal it will hesitate for a second. It hasnt always done this just for the past 6 or 7 months. I have taken it off and cleaned it, adjusted the mixture screws, even tried putting different accelerator cams on it and same result. I bought the carb new about a year and a half ago. Do I need to replace the power valve and give it a rebuild already? Any help would be appreceiated. THanks!!


Douglas.

[Oldtruckfanatic]

I would look closely at the accellerator pump. It should squirt fuel from the nozzle with a decent amount of pressure when you open the throttle if it's just a weak stream it's probably got a bad diaphram or blocked fuel passage. All of this is assuming you have a good clean air filter and the tune up specs are acceptable. Mine was running crummy here a couple of weeks ago and it turned out my K&N air filter was all clogged up. (I clean it regularly but I guess I used too much filter oil last time). Hope you get it figured out.

[JAKES 68GMC]

My truck was doing this with a 500 2bbl. We messed with the timing and problem solved.

[hgs_notes]

I agree with oldtruckfanatic. Probably the accelerator pump. Might also be clogged spray nozzle on the accelerator pump.

[clif1968]

Sounds like the pump cam or pump arm is out of adjustment. If the carb is only a year and a half old the accelerator pump should not be bad. With the engine off look down the carb and barely crack the throttle, you should see spray with the slightest movement. If there is no squirt you have to much slop in the pump arm, or the cam is in the wrong position.