Having a problem with fast idle and normal idle need help bad

[lx 1986]

Have a 86 honda Accord LX 2.0L, 2bbl Keihin carb, auto trans

I had remanufactured carb installed. On cold start the fast idle goes up to 3000 rpms then drops to the line right below 3000. The fast idle doesn't come down on it's own I have to wait until temp goes up to get it to gradually come down by tapping the gas. Before this problem, on cold start it would warm up normally (highest 2500 rpms) then gradually come down on its own to operating range.

I also noticed after driving it for a half hour or more when I restart the car after about 5-10 mins it goes into fast idle again. I have to wait till the car gets hotter for the idle to come down and then the idle hangs above 1000 rpms in park and 900 rpms in drive. The car runs rough and gets hot. Normal for this car is 1000 rpms in park or neutral and 800 in drive. Once and awhile when I put it in gear the idle will drop down.

I had 2 mechanics try to adjust the idle. 1st one said it was the throttle cable. Replaced that and still same problem. 2nd one says that the throttle stop scew wasn't working and he couldn't adjust fast idle or idle.

The 1st mechanic tried to adjust the idle when it would hang when the car was operating temp. He lowered the idle down to 1000 rpms in park. When I would start the car in the morning the fast idle would go to 3000 rpms and wouldn't come down on its own still, but when I did get it to come down the normal idle would be below 1000 rpms. Why does the idle keep dropping below 1000 rpms when the car is warmed up after cold start?

The 2nd mechanic was trying to adjust the fast idle and said that something was wrong with the throttle stop screw and it wasn't adjusting. It might be broken he said.

Why is my throttle stop screw not adjusting the idle?

Does the throttle stop screw have anything to do with the fast idle adjustment?

Why does my idle hanging at times when the car is in park or drive and warmed up?

[Hauntd ca3]

1000rpm is to high in park , 800 is about right .
Is the throttle cable slack at the carb or taught .
It should be slack other wise the cable will influence cold idle and warm .
Get the cable set up properly, get the cengine warm and set the idle at about 800 =/-50 and work from there.
Warm idle in gear should be roughly 700 .
Pull the air cleaner assembly off , make sure the cable is set up slightly slack( you should be able to move the cable side to side a bit without effecting engine speed ) then back the idle speed screw in and out a bit to see if its working .
If its working , back it out until the engine nearly stalls and then wind in until you get to 800 rpm in park or neutral.
Let it cool enough to get the choke to engage and see what happens .
a small misadjustment of the cable or throttle stop can make big changes

[lx 1986]

Hauntd ca3

Thanks for responding. I will try what you said and see what happens.

When you say idle speed screw do you mean throttle stop screw that's in the back of the carb (black knob)?

[Hauntd ca3]

Yep , the knob is usually the idle speed adjustment on jap carbs.

[lx 1986]

Hauntd ca3

The cable has about a 1/2 inch play when cold and 1/4 when warm.

The air cleaner wasn't off completely because the car ran rough so I took it off partially so I could reach the throttle stop screw. It does work. For some reason when turned to increase idle it seems real tight almost like it was screwed in all the way. I used some curved pliers to turn it. When I decreased the idle the knob can be moved by hand real easy.

I didn't adjust the throttle stop screw as yet. What I need to know is before I make adjustment to the trottle stop is it alright to have the air cleaner off completely?

Next is I need to know what the silver screw with the spring that's located right below the cable on the left side of the carb what does it adjust? I was told this is for the fast idle adjustment.

Do I need to back that screw out along with the screw on the right side of the carb (I believe it's the adjustment for the ac) so they don't affect the throttle stop adjustment? Reason I ask is some of the members say this is what they do. I'm not sure if they have the same carb.

[Dr_Snooz]

Are you sure your choke isn't sticking?

[lx 1986]

Dr Snooze

No the choke isn't sticking.

Can you tell me what the silver screw with the spring on it, that's located right below the cable on the left side of the carb what does it adjust? I was told this is for the fast idle adjustment. Is that right?

That would help me a lot.

Thanks