Holley Colored Pump Cams

[7991LXnSHO]

Does anyone know which of the ac. pump cams does what? I have a spot off idle and off low throttle that falls on its face for a second before scooting. So I bet it needs a bigger initial shot. Also, should I use the b or a position for the screw in the cam and throttle arm? My carb book just says experiment, and there has to be a better answer on the vac. secondary carbs.

 

[CarMichael Angelo]

Does anyone know which of the ac. pump cams does what? I have a spot off idle and off low throttle that falls on its face for a second before scooting. So I bet it needs a bigger initial shot. Also, should I use the b or a position for the screw in the cam and throttle arm? My carb book just says experiment, and there has to be a better answer on the vac. secondary carbs.

I'd say that the reason your book says "experiment" is because there is no cut&dried end result when making the adjustment. I was never too lucky w/ pump cam adjustment, but then again, I was never trying to finess a hesitation out of my carb.( most were on drag cars)
throttle crispness/response was always a squirter, and acc pump adjustment for me

 

[7991LXnSHO]

Until I can experiment, if I do not like the stumble, I will have to open the throttle granny style or just stomp on it. Guess which one way is more likely.

 

[CarMichael Angelo]

Until I can experiment, if I do not like the stumble, I will have to open the throttle granny style or just stomp on it. Guess which one way is more likely.

bigger pump shot,increase the acc pump shooter.

 

[7991LXnSHO]

That will be another step. It is good that I am not the only one old and wise enough to know how a carb works. I am guessing the pump is big enough since flooring it produces no sag. If the cams do not help, then off to the speed shop I go for a bigger pair of squirt nozzles assembly.

 

[7991LXnSHO]

I found a cam that works better in the B position. But it still stumbles a bit when loaded or cold, so the bigger squirters are going in. They come in pairs, so I'll have an extra.