puddlejumper75

Working on a 75 for a friend of mine has the L-48. It idles pretty rough, I'm guessing vacuum issue cause there are a lot of vacuum hoses missing. And also when you hit the gas hard from a dead stop it bogs down almost shutting off then finally goes...need some help.

PuddleJumper

What rpm is your idol set at.. I got a L48 im working on and it dont get smoth untill 900 for idol..

Could be timing too..

puddlejumper75

At idle is around 1500

PuddleJumper

can you make it idol any lower?


something to watch.. but your issue might be something else too

puddlejumper75

Well after looking at it a second ago my tach isn't reading properly....took it down and around the block and came back, shut it off and tach is stuck at 2000rpms

gsimon767

Tach board is fried. Will need to be replaced.

Assuming no vacuum leaks, timing set to spec and stock Quadrajet, idle needs to be set at 600 RPM and idle screws adjusted for highest steady vacuum. Should be out about 2-3 turns. If idle raises above 600 readjust and repeat idle screw procedure. Bog off idle can happen when throttle plate is too open allowing too much air making idle screws unresponsive. Transition off idle circuit to primary circuit will be off.

Bog could be accelerator pump shooting too little or late but try idle screw adjustment before anything else.