Author Topic: 84 GMC throttle return  (Read 2780 times)

Offline Tommyd11730

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84 GMC throttle return
« on: December 29, 2016, 07:15:09 pm »
Guys, do the quadrajet carbs have a return spring of their own?  Seems as though I need way too much throttle return spring tension to close the throttle.

Thanks!
1991 K5
1984 K2500

Offline bd

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Re: 84 GMC throttle return
« Reply #1 on: December 29, 2016, 07:51:16 pm »
Will the throttle close correctly with the throttle and transmission cables disconnected from the carb?  Is the choke releasing completely and the fast idle cam dropping out of the way?  With the choke fully open, crack the throttle open ~3° and wiggle the throttle shaft fore and aft.  If there is greater than ~1/64" of side-to-side play in the shaft, the shaft bore is worn out and the throttle plates are not centered, causing them to hang up on one edge.  The solution is to rebush the throttle shaft bore.  If there is 1/64" or less of radial play and the throttle plates are hanging in their bores, you can try recentering the plates.
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline Tommyd11730

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Re: 84 GMC throttle return
« Reply #2 on: December 29, 2016, 10:41:01 pm »
Truth be told I didn't disconnect the throttle cable, however the TV cable I did disconnect.  Funny it actually acts to some degree like a return spring.
Correct we talking off high speed cam.... it's very possible the shaft needs to be rebushed.  The truck only has 74k but at some time the carb was replaced.  No clue how many hours it's seen.
1991 K5
1984 K2500

Offline 82silverado

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Re: 84 GMC throttle return
« Reply #3 on: January 06, 2017, 05:41:23 pm »
I always go with two springs. A smaller diameter spring inside of a larger diameter spring. Both the same length.
82 Silverado 454/700R4
86 Buick GN
02 WS6