Cliff's Quadrajet Parts and Rebuild Kits

General Category => Quadrajet Carb Talk and Tips => Topic started by: A.G.V.chevyfreak on November 13, 2019, 01:52:13 AM

Title: Qjet main jet change effect
Post by: A.G.V.chevyfreak on November 13, 2019, 01:52:13 AM

Hi all.
Just a general question.
On a qjet.
Nothing changed apart from mainjet.  Lets say 70 jet changed to 73, will it have an effect on the idle circuit?
I know without change in metering rod it will have an effect to cruising and wot . But wondering if it alters the idle circuit metering.
Thanks.

Title: Re: Qjet main jet change effect
Post by: Cliff Ruggles on November 13, 2019, 02:18:59 AM

In theory no, but considering that all the fuel to the idle tubes has to pass the jets with the metering rods down.

If you've got some huge metering rods sitting very low in the jets to a point where it restricts the flow some, or considerably less metering area than the size of the idle tubes it could restrict fuel headed to the idle tubes.  Typically this doesn't happen but I see the potential for it to happen if the hanger arms are bent way down and pretty big metering rods being used in pretty small jets, etc......Cliff 

Title: Re: Qjet main jet change effect
Post by: A.G.V.chevyfreak on November 13, 2019, 03:56:56 AM

Thanks cliff.