Author Topic: Carb link and and throttle return spring w/pic  (Read 1930 times)

Offline mcintyrederek

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Carb link and and throttle return spring w/pic
« on: August 06, 2015, 11:05:32 am »
I just thought I'd share this pic I found while browsing around the web.  I have overlooked this on my vehicle and I wonder if anyone else has.  I never paid it any attention until I took my Q-jet apart and noticed how incredibly worn the tab was on the throttle plate hinge.  My setup was like the "bad" picture but I never even thought about it.  When the Edelbrock goes on, I'm going with the bell crank method.

Mack.
1986 C-10 Silverado 350 CI 260 HP, Edelbrock 1405, TH400, 2.73's - rescued from the junkyard - Farm Truck, daily driver!

Offline enaberif

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Re: Carb link and and throttle return spring w/pic
« Reply #1 on: August 06, 2015, 11:42:11 am »
Bad and Poor examples are one of the reasons why the shaft bushings on a lot of the quadrajets wear out. I've never understood the "Best" situation because I don't understand the bell crank part of the assembly.

Offline mcintyrederek

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Re: Carb link and and throttle return spring w/pic
« Reply #2 on: August 06, 2015, 02:29:41 pm »
It looks like to me that the "better" and "best" examples should be the same -- NO force on the plate hinges at ALL..  The "better" example should be no problem at all assuming you can be for certain that your return spring is lined up EXACTLY opposite of the throttle cable, of course that's in a perfect world and positioning it just so might be very difficult to do.

The bell crank is best because any force and wear & tear is done on the bell crank hinge which would be a bushing, bolt, etc. on the bottom of the lever of the bell crank.  Then, the carb throttle plate only sees action from a passive rod that just pushes and pulls back and forth on the throttle link between itself and the top of the bell crank so there can be no force on the throttle plate hinges at all.

Reminds me of the air governor and throttle cable linkage on a 3.5 Briggs lawn mower engine. 

Mack.


1986 C-10 Silverado 350 CI 260 HP, Edelbrock 1405, TH400, 2.73's - rescued from the junkyard - Farm Truck, daily driver!