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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: 505090 on August 19, 2010, 02:43:59 pm

Title: even bank not firing???
Post by: 505090 on August 19, 2010, 02:43:59 pm

I have a 77 small block 350 I am fixing for a friend. At this point I am trying to adjust the carb (4 barrel rochester). RPM is at ~800 and I am adjusting the two mixture screws on the front base using a vaccum gauge. My problem is the right bank is setting to ~4 turns out and the left is setting to ~.5  In the past when I've done this both sides have been in close proximity to each other. Not sure what the problem is or what would cause it.

Any ideas appreciated, thanks for your time.

Title: Re: even bank not firing???
Post by: beastie_3 on August 19, 2010, 03:08:46 pm

What is the condition of the carb? Fresh rebuild?

When you say its not firing, are you not getting spark? Or is it the lack of fuel?

Title: Re: even bank not firing???
Post by: Grim 82 on August 19, 2010, 03:24:39 pm

Start at 1 1/2 turns or so out on each, and if it runs back them out equally, half turn at a time until you get the highest vacuum reading. Adjust your idle speed from there.

Title: Re: even bank not firing???
Post by: VileZambonie on August 19, 2010, 04:19:18 pm

The idle mixture screws don't feed the odd and even cylinder banks. Adjust them until you have the best idle quality.