lean just off idle (not accel pump)
09-06-2002, 02:02 PM
#1
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Car: RS
Engine: LS1
Transmission: T56
Axle/Gears: 9" for the ladies
lean just off idle (not accel pump)
If you just barely give it some throttle from a stop in city driving it hesitates.
Its going lean because if you give it a little more, enough for the accel pump to work, it goes fine. So what can I do about that flat spot just before you give it enough for the pump cam to operate the squirter?
I adjusted the idle on both sides of the bowl but that won't fix it.
Thanks
Holley 750VS
Its going lean because if you give it a little more, enough for the accel pump to work, it goes fine. So what can I do about that flat spot just before you give it enough for the pump cam to operate the squirter?
I adjusted the idle on both sides of the bowl but that won't fix it.
Thanks
Holley 750VS
09-06-2002, 04:31 PM
#2
Supreme Member
You need to adjust the accelerator pump linkage so that fuel comes out of the discharge tubes right as soon as you move the
throttle linkage. You can adjust the height of the spring and or bend the linkage arm. You can move the mounting position of the plastic cam too. Different cams have different shapes also.
Get some and try them.
Carbon Fouled spark plugs will cause that stumble too.
So can a vacuum leak.
If you have a big (low vacuum) camshaft, Your car may be idleing with the throttle plates too far open, exposing too much of the transfer slot. This can cause a flat spot when coming off idle too. The cure is to open up the secondary throttle butterflies a small amount to allow you to close the primaries back to the proper position for correct idleing. Thus the idle will be equally shared by the primary and secondary barrels. About .020 to .030" of the transfer slot should be exposed under the throttle blade at idle. You have to remove the carb to see the transition slot/ throttle blade position.
throttle linkage. You can adjust the height of the spring and or bend the linkage arm. You can move the mounting position of the plastic cam too. Different cams have different shapes also.
Get some and try them.
Carbon Fouled spark plugs will cause that stumble too.
So can a vacuum leak.
If you have a big (low vacuum) camshaft, Your car may be idleing with the throttle plates too far open, exposing too much of the transfer slot. This can cause a flat spot when coming off idle too. The cure is to open up the secondary throttle butterflies a small amount to allow you to close the primaries back to the proper position for correct idleing. Thus the idle will be equally shared by the primary and secondary barrels. About .020 to .030" of the transfer slot should be exposed under the throttle blade at idle. You have to remove the carb to see the transition slot/ throttle blade position.
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