fredneck872 Posted March 18, 2011 Report Share Posted March 18, 2011 I am having problems adjusting the carb to get the idle up,its A brand new rebuild,rochester 4GC 7009750 ,when I mess with the idle by pass witch the manual says to raise or lower idle doesnt work. Any help i Link to comment Share on other sites More sharing options...
johnnyjaws Posted March 19, 2011 Report Share Posted March 19, 2011 screw the adjustment screws in the lower front of the carb one on the left and one on the right dont over tighten and back out 3 turns each start car and go in 1/4 or out 1/4 were ever you get the highst idle and that should do it 2 raise the idle faceing the front of the car on the right side of the car the idle screw is on the side of the carb Link to comment Share on other sites More sharing options...
fredneck872 Posted March 28, 2011 Author Report Share Posted March 28, 2011 screw the adjustment screws in the lower front of the carb one on the left and one on the right dont over tighten and back out 3 turns each start car and go in 1/4 or out 1/4 were ever you get the highst idle and that should do it 2 raise the idle faceing the front of the car on the right side of the car the idle screw is on the side of the carb Link to comment Share on other sites More sharing options...
fredneck872 Posted March 28, 2011 Author Report Share Posted March 28, 2011 Thanks for the info, I played with the idle screw,witch is in the middle of carb by throttle linkage, correct?,when I screw that in or out it doesnt really raise the idle it just sucks more air. Link to comment Share on other sites More sharing options...
mike5514 Posted March 29, 2011 Report Share Posted March 29, 2011 First set your timing to what the book says around 10 before top dead center (the vac advance line should be disconnected at the distributor then pluged) then like johnny says turn in the 2 front mixture screws untill seated use fingers only. Then with a screwdriver back out each mixture screw 1 and a half turns. Adjust idle speed screw to book value around 650 to 700 rpm stay away from the secondary valves and choke adjusting screws. If you have the external adj. points on the distributor using a allen wrench screw clockwise untill engine misses then back out till miss goes away, check idle speed and timing again, unplug vac. line a put back on distributor. Then using your timing light check to see if you have vac. advance. Its been a while since I did this but it should work.Mike Link to comment Share on other sites More sharing options...
fredneck872 Posted March 29, 2011 Author Report Share Posted March 29, 2011 thanks mike, i'll play with it somemore, I think the timing might be the problem but book says to check at 400 rpm thats hardly running, I might have to do it by ear, Link to comment Share on other sites More sharing options...
mike5514 Posted March 29, 2011 Report Share Posted March 29, 2011 fredneck you can do it by ear. Get in car and put it in drive when you take foot off brake it should feel like it wants to creep forward, rpm will now be around 400 to 450rpm. When adjusting idle speed make sure vac line is connected to distributor. To check for vacuum advance with engine running pinch and disconnect vacuum line at distributor the rpm should drop. To review (trans. in neutral adjust idle speed screw for around 700rpm)(trans in drive 400 to 450). I dont like to adj. rpm with trans. in drive without someone holding the brake down. Mike Link to comment Share on other sites More sharing options...
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