I have a 350 engine with a 4150 vacuum secondaries 600 CFM. Car stumbles or bogs when you give it some gas, worse when it is cold. Choke is working proper, set accelerator pump to specs and it seemed worse. Increased the shot and it was better but not enough adjustment. The engine is stock would I need to increase the accelerator pump size? Timing seems to be on.
Thanks I will give it a try. I have never run into timing affecting the stumble, but of course I always ran lots of advance in the "old" days on my Chryslers.
Also check your float levels . Make sure your getting fuel in the rear bowl. I have seen new carbs with float levels set wrong. Could be starving for fuel. Does not hurt to check. Like randy said timing. Would not hurt to ad a few degrees. You can always put it back.
Thanks Randy I will give it another try with the timing, I have checked and have no vacuum leaks and have tried playing with enriching and leaning out and doesn't make any difference. I forgot to mention that is does have a one inch spacer on the carb so don't know how much that would change flow characteristics
did you check this little khown adjustment on a holley 4 barrel....from under the carb there is a secondary throttle plate adjustment..a small screw that should be turned 1/4 times to provide a little fuel to prevent a stumble (google Holley carb adjustment--good info)
-- Edited by beaucarlo on Thursday 20th of July 2017 12:54:02 PM
as a quick experiment , rev her up to about 1200 lay your hand over the air horn does the rpm go up or down, rich is down, I have to play with the holley in the Camaro every time I drive it , finicky to a carter
I set the timing to 20 before TDC and tried a bigger accelerator pump nozzle 25 to 35 no bog when it is warmed up now, still a bog when it is cold, so will have to keep tuning.
i searched Holley carb adjustments....in the list there is a section -Rebuild and Adjustment Manual for Models 2010,2300,4010..Holley- from the manual i took a picture
with my cellphone to post it.......the trouble with this adjustment is you have to remove the carb to adjust...if you have a bigger cam some people suggest turning the
screw 1 1/2 turns then adjust the 4 idle screws using a vacuum guage and a tach
The engine is stock, the carb looks old and may have been thrown on it to just to sell it. I have never had so much trouble with a carb or tuning it before.
sounds like you recently bought your car.....a carb gets blamed for alot of issues...start with a good basic tuneup...including a compression test....make sure the timing is to spec. ,vacuum advance is operating,no vacuum leaks, no cracked hoses correct pcv valve(new hose)last to set is the carb i don,t know your engine size-maybe you have the wrong carb or jet size....sounds like you are close...