Author Topic: Idle & Main circuit relationship  (Read 1223 times)

Offline CJK440

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Idle & Main circuit relationship
« on: April 18, 2018, 05:39:26 AM »
So I got my carb rebuilt with bunch of parts from Cliff and want to fine tune things going forward.

From what I understand, the secondary system is completely stand alone. But since the fuel for the main and idle system passes thru the jets first, I want to understand what relationship there is if any.

Right now my carb idles fine. I opened idle bypass air to keep the primary plates at a reasonable close point (the driver side ported vacuum distributor port shows a couple in/hg at idle while the pass side EGR ported vacuum fitting has none).

If I adjust the jets or main rods, should I expect to possibly have to balance my idle calibration to compensate? Or do the jets flow much more fuel than the idle circuit needs, making any jet/rod changes transparent in regards to idle calibration?

Offline qjetsrule

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Re: Idle & Main circuit relationship
« Reply #1 on: April 23, 2018, 01:57:45 AM »
If you followed Cliff's recommendations for the jet/rod combination you should have ample fuel to supply the idle tubes. You shouldn't have to touch your mixture screws if you adjust the primary metering rods, there's plenty of fuel for the idle circuit. Good luck.