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73-87 Chevy _ GMC Trucks => 73-87 Chevy & GMC Trucks => Topic started by: tjwelch2012 on December 10, 2013, 07:58:07 am

Title: Throttle help
Post by: tjwelch2012 on December 10, 2013, 07:58:07 am

I have a '76 C20 454 big block.  I'm having trouble with it idling too high.  So high that I can go about 30mph without pushing the gas pedal.  I have to give it a quick goose on the gas pedal before it idles down to normal.  Any suggestions??

Title: Re: Throttle help
Post by: darmentle on December 10, 2013, 08:14:38 am

What type of carb are you running?

Title: Re: Throttle help
Post by: 81_Chevy on December 10, 2013, 09:10:36 am

Quote from: darmentle on December 10, 2013, 08:14:38 am

What type of carb are you running?

x2

and is this while its cold or hot?

Title: Re: Throttle help
Post by: 454Man on December 10, 2013, 09:47:25 am

Seems like the Fast idle screw needs adjustment. If the carb has one its easy to do

What's under the hood??? If you have to ask maybe we shouldn't race!

Title: Re: Throttle help
Post by: blazing816 on December 10, 2013, 10:46:44 am

Quote from: 454Man on December 10, 2013, 09:47:25 am

Seems like the Fast idle screw needs adjustment. If the carb has one its easy to do

X2

My truck had same symptoms as yours, and I did what '454Man' said. Found the fast idle screw and turned it down (and I mean mine was jacked, I had to adjust pretty far). What I did until I figured out it was fast idle from these forums, is just un-hooked the choke. It was harder to start cold, but mine was jack up so high I thought it would blow my engine, it was at like 3500-4000 rpms

Title: Re: Throttle help
Post by: bd on December 10, 2013, 12:06:54 pm

OE Specs:
Fast idle should be adjusted between 1,600 - 1,700 RPM in neutral with engine at operating temperature and fast idle screw on highest step of the fast idle cam.