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73-87 Chevy _ GMC Trucks => Performance => Topic started by: coolcuz820 on November 21, 2004, 09:46:00 pm

Title: running rich, seems like?
Post by: coolcuz820 on November 21, 2004, 09:46:00 pm

I have 79' C20 with a quadrajet. It smells like its running rich. which out of the two screws should i turn to make more lean? and which way to turn and how much?

Title: Re: running rich, seems like?
Post by: roundedline on November 22, 2004, 02:11:00 pm

It is a combination of both screws that you need to adjust.  Set the timing to around 8-10 degrees (disconnect the vacuum advance), set the idle for around 750rpm , get a vacuum gauge connected to a non ported source and starting with the screws 1/2 turn out move them in 1/4 turn increments until you achieve the highest vacuum reading, then turn it back about 1/8 -1/4 turn.  The reading should be steady, if not, you have other potential problems.

Chris Lucas
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