Hoping some here can advise. Just replaced my aging Holley on my Pantera 351C with a Quick Fuel HR-600 carb (mechanical secondaries). Went through all the set up and tuning. Got strong vacuum of 17+ inches and set 4-corner idle. Quick Fuel installation guide says nothing about setting or changing factory settings out of the box on the primary and secondary accelerator pump arms. So, watched the videos on YouTube (probably a mistake) and adjusted the lash on the arms to less pre-load (supposedly you are to set to zero lash). Upon doing, car throttle response was shit. Falls flat on its face with any throttle advance. So I adjusted back to the pre-load that came out of the box and it responds well again. So my questions for this group are:
1. Should accelerator pump arm have some amount of preload? (when I push arm up against the actuator arm spring, I get about 1/8" to 3/16" inch travel of threaded rod / nut above the arm.
2. Is this actually the case of the arm should have zero pre-load but my pump nozzles are undersized and creating that flat spot? (nozzles are 0.28" from factory)
I appreciate your insights on this.
1. Should accelerator pump arm have some amount of preload? (when I push arm up against the actuator arm spring, I get about 1/8" to 3/16" inch travel of threaded rod / nut above the arm.
2. Is this actually the case of the arm should have zero pre-load but my pump nozzles are undersized and creating that flat spot? (nozzles are 0.28" from factory)
I appreciate your insights on this.