carb problems? or choke?

[IL84JIMMY]

I drive an '84 Jimmy, I am having problems with really high RPM's. I am not a mechanic, so i need some help. Almost everytime i fire it up, the RPM's jump up to 2000 or above, and stay there until i kick the gas and then it goes down. But as soon as I start driving again, they are right back up where they were before. I drive a manual, so it is not like the truck runs away from me, but it always wants to be at about 2000 RPM's, when i am driving, or put the clutch in, or sitting in nuetral it is all the same. Is this a problem with my electric choke, or carb, or just a throttle cable, or something completely different? With gas prices where as high as they are, this is getting expensive. thanks for any help.

 

[pauly383]

Sounds like linkage problem/choke to me. The fact that it idles down on first kick is good, but it shouldn't go back up. Make sure nothing is in the way, and the choke wire has 12 volts to it . /forums/images/graemlins/k5.gif

 

[IL84JIMMY]

Could I use some carb cleaner as wd40? or what would be best? I have been gone all weekend and havent been able to work on it, but I will tomorrow. thanks for the info.

 

[IL84JIMMY]

Also guys and gals, I forgot to mention, I had a guy who pretty knowledgable driving my truck and he told me that my secondary ports on my 4 barrel carb aren't opening when i get onto it. I have never driven a truck with a good running 4 barrel rochester to know what my power should be. How can i tell if these ports are opening. Can i just look at the carb as i manually give it the gas right there and see if they open? If they are in fact not opening, what can/should i do? Thanks again

 

[v-3500]

It sounds like, to me, your throttle shaft is worn out. When the throttle shaft and the bore it rides in wears out, the butterflies in the carburetor base plate jam partially open, thus hanging the throttle partially open. This is a major problem with Q-Jets.

 

[GMCLegacy]

does it remain on high idle all the time? or will it remain on normal idle after you have driven it for a while down the road to get the thermostat opened? is there a wire running to the round black plastic cap?

 

[IL84JIMMY]

When i drive home for weekends, most of the time, by the time i get home everything is running fine. But if i go back out after i am home for a half hour, it will jump back up. I think there is the wire you are talking about running to the black cap, if i am looking at the right thing. If it is my throttle shaft, will that mean a new carb for me? If i do need a new one, what would anyone recommend? my truck is 99% DD and 1% muddin when we get some rain and I am home in the country. Thanks for all the info thus far. I am always open to more. Thanks