So I was dissecting some Quadra jets and noticed this difference in the springs on these 2 power pistons. Are these 2 springs comparable or does one have more resistance than the other? What would be the benefit of having a stiffer spring? I think the left is from a 71 and the right from a 72.
The power piston spring is probably one of the most important adjustments in a q-jet and probably the most overlooked. The stiffer the spring the more vacuum required to open it up. Generally speaking the bigger the cam the lighter the spring should be. Too weak of a spring will cause a hiccup as bad as a worn out accelerator pump. Too heavy and it'll be pig rich.
Hum... interesting. So the left one came from a carb that backfires out the carb and sputters when you hit the accelerator hard. Maybe that spring is too light.
Those conditions indicate more of a lean issue. It might be too weak especially if that motor has a bigger than stock cam. Edit- i got my lines crossed..
It's all stock. Adjusting secondary air door tension didn't seem to make it any better either. I should order a stock spring since I don't know what was done to this carb for the 40 years before I got it.
