goldduster318
Overzealous Car Modifier
Hello all,
I have a Quick Fuel SS-750-AN, 750cfm Annular Booster Double Pumper carb on my 340. This carb seems to run great in all areas except right off of idle and if you get into the throttle a little bit at low RPM in 4th gear.
The car is a '70 Duster, full weight, 4-speed, and 3.23 gear.
Primary Jet: 68
Secondary Jet: 78
Idle Air Bleed: 69/69
High Speed Air Bleed: 29/29
Primary Squirter: 31
Secondary Squirter: 31
Power Valve: 8.5
Fuel Pressure is 6 psi with a regulator and the fuel level in the bowls is just slightly below the center of the window.
I have a wideband on it, and I'm satisfied with the A/F at any rpm above 2300, below that it seems to go lean/rich a bit depending on RPM/load
At idle, the A/F ratio is between 13.5 and 14:1 (950rpm)
When I pop the clutch, the engine stumbles and leans out on the wideband into the 16-17:1 range for a second then recovers. In many cases it becomes a bit rich after this.
Any ideas on how to get rid of this stumble? I've tried several accellerator pump cams and haven't really gotten rid of it. It seems to be best with either the brown or green pump cam.
Thanks for any help!
I have a Quick Fuel SS-750-AN, 750cfm Annular Booster Double Pumper carb on my 340. This carb seems to run great in all areas except right off of idle and if you get into the throttle a little bit at low RPM in 4th gear.
The car is a '70 Duster, full weight, 4-speed, and 3.23 gear.
Primary Jet: 68
Secondary Jet: 78
Idle Air Bleed: 69/69
High Speed Air Bleed: 29/29
Primary Squirter: 31
Secondary Squirter: 31
Power Valve: 8.5
Fuel Pressure is 6 psi with a regulator and the fuel level in the bowls is just slightly below the center of the window.
I have a wideband on it, and I'm satisfied with the A/F at any rpm above 2300, below that it seems to go lean/rich a bit depending on RPM/load
At idle, the A/F ratio is between 13.5 and 14:1 (950rpm)
When I pop the clutch, the engine stumbles and leans out on the wideband into the 16-17:1 range for a second then recovers. In many cases it becomes a bit rich after this.
Any ideas on how to get rid of this stumble? I've tried several accellerator pump cams and haven't really gotten rid of it. It seems to be best with either the brown or green pump cam.
Thanks for any help!