fast idle on Rochester 4Bbl

[vervepipes]

i bought an 84 k5 with a 305 and rochester carb, the choke wasnt working when i got the truck and in the process of fixing the choke, i think i did something to the fast (cold)idle. the story:
i took off the electric choke and put on a universal hand choke, which freed the choke. at some point the fast idle got stuck and was on all the time, then it just stopped engaging when i started. the new choke cable then stuck, so i'm back with the electric (happy now with its working condition) but the cold idle does not engage unless i manually engage the linkage while the truck is running. i dont like having to sit in the truck with my foot on the gas for 5 minutes till its warm enough to hold it own, anybody have suggestions on something i may have overlooked?

 

[pauly383]

I can find you picture later when I get home from work , unless someone helps beforehand

 

[vervepipes]

bump, nobody's had this problem and figured a solution?

 

[ryoken]

maybe you got the choke lever on the wrong side of fastidle lever when reinstalling the choke? if i remember correctly, the fast idle cam is on that side too. if ya want i've got a couple downstairs and could shoot a pic...

 

[pauly383]

Got sidetracked and forgot , looking for somestuff on my end now too

We can start with this typical smog era q-jet , just ignore the drivers side electrical stuff .

 

[vervepipes]

i used a miltimeter and made sure current made its way to the choke. that works. i believe #348 on your diagram is where the choke mated to the linkage with the fork, and there's no way that could be mated wrong: it's either obviously on correct or on wrong, no in-between. it's har to tell without having my carb right in front of me, but the fast-idle lever is either #352, 350 or 360 (if i recall correctly, the lever is labled "Y" on the actual carb) and it wont engage unless manually push up on the lever and give some gas at the same time. then it will act normal and as it heats up it will turn to a slower idle. when i start the truck later, it will once again not have the fast idle engaged unless i start the process again. it's as though there's some linkage is missing or disconnected keeping the lever from returning to the fast position as the choke element cools, but i couldnt see anything physically wrong when i looked. i'll try to print the drawing at work next week then compare it to my linkage

thanks,
Francois

 

[pauly383]

When you remove and reassemble , try to lightly polish the surfaces whereever it wears , and then some moly lube or something on there , something that lubes but doesn't draw too much dust and dirt into it . It should just fall when you get into the truck in the morning and pump the carb ( or twice or thrice if its really cold out ) to reset it

Oh , and thank Dorian Yeager for the pic ( ck5 member as well ) its off his q-jet page