I've searched and can't find anything so I'm sorry if this has been discussed. I have a mild to mediocre 454 with a 750 holley vacuum secondary. I have a stumble that I can't get rid of.
I have a 50cc accelerator pump with the yellow cam and right now I have a .050 pump nozzle with the hollow screw. I know that's too big but I'm trying to figure out this stumble. I can be cruising along and the afr is around 14.5. I mash the gas and the afr goes to 17.0 for maybe a half second then goes to 10.0 for a second or 2 then settle out at about 13.5 (power valve open.) The going to 10.0 makes sense because of the huge nozzle but it's still hitting 17.0 for a split second which makes no sense to me.
If I'm cruising along around 14.5-14.7 and gently roll on the throttle it will go to 16.0 for a split second then go to 12 or so and come back to the mid 14s if I hold it there.
What can my problem be? I have no slack in the pump lever and still have some room left at WOT. With the current nozzle, it shoots 2 huge streams of fuel when I open the throttle. It starts squirting as soon as I start to move the throttle. I have the secondaries wired shut until I get this figured out to rule that out.
I have a 50cc accelerator pump with the yellow cam and right now I have a .050 pump nozzle with the hollow screw. I know that's too big but I'm trying to figure out this stumble. I can be cruising along and the afr is around 14.5. I mash the gas and the afr goes to 17.0 for maybe a half second then goes to 10.0 for a second or 2 then settle out at about 13.5 (power valve open.) The going to 10.0 makes sense because of the huge nozzle but it's still hitting 17.0 for a split second which makes no sense to me.
If I'm cruising along around 14.5-14.7 and gently roll on the throttle it will go to 16.0 for a split second then go to 12 or so and come back to the mid 14s if I hold it there.
What can my problem be? I have no slack in the pump lever and still have some room left at WOT. With the current nozzle, it shoots 2 huge streams of fuel when I open the throttle. It starts squirting as soon as I start to move the throttle. I have the secondaries wired shut until I get this figured out to rule that out.