Cannot get RPMS to drop down on cold start

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EastTXTraveler

New member
Got a new Holley 2300 carb about a year ago with the electric choke conversion. Everything was setup, running good for over a year. However, recently I have noticed that when staring the Scout cold, I cannot get the 345 to drop down to curb idle rpms. I can visually watch the choke plate open up, but no matter how much I tap the gas pedal, I cant get the rpms to drop down. As a matter of fact, when I tap the gas pedal it revs the engine more, and it holds the increased rpms.

Today, the needle on my stock temp guage was almost to the first tickmark and the engine was still at fast idle.

Like I said, this has been a recent issue. I appreciate any help I can get. Truck is a 78 Scout traveler with a 345/727 and Holley 2300 and dui ignition.
 
Sounds like the 'fast idle cam' May be sticking. When the choke flap closes, the 'fast idle cam' is pulled to make the engine idle faster for the cold start. When the choke opens. The fast idle cam is 'supposed' to drop back due to a heavier weight on the foreward edge. The 'tapping' of the throttle should release the pressure against the cam so it can drop back and allow the engine to return to base idle. If not, and the engine has heated, the plastic cam might be sticking, preventing proper operation. Try squirting some carb cleaner on the passenger side linkage and cam. There should have been instructions with the carb showing the parts.
 
Bill, thanks for the reply. I had a chance to check out the choke mechanism this weekend.

The red plastic piece which I believe is the high idle cam is getting caught on the mount that attaches the electric choke mechanisim to the body of the carb. I can push the red piece down into position manually with my finger.

It's almost like the plastic gets cold and expands, and when it does it won't clear the mounting piece. I noticed that after the engine is warmed up it does clear like it's supposed to. It hangs up evertime when I start the Scout in the morning after sitting all night.

Any advice would be appreciated. The choke works fine other than this. Clipping or shaving the red plastic piece seems like it would fix the problem but that just doesn't seem right.
 
There May be some crud/dirt on the choke linkage or inside the choke adjusting can. Is this something that just started to be a problem? Try removing the choke working linkage and check for the 'sticking' part. Shouldn't need to 'file or cut' anything. Do note the location of the notch and 'tick marks' on the adjuster so you can put it back together in the same position. Did you try spraying the choke linkage with the carb cleaner?
 
Bill, thanks for your help. I am definitely a novice to working on a truck, but trying to learn.

I did spray carb cleaner on the linkage, and the linkage itself does not seem to be binding. I will watch the the choke plate open up like it is supposed to, however the red plastic piece (I don't know what it's really called) that drops down when you tap the gas pedal is getting stuck. It isn't getting stuck by much as I can easily push it into position with my finger.

This issue just started recently, and it's just annoying. I will try to take a picture this afternoon and post it up so you can see what I am talking about.

Thanks again for your patience
 
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