carb running to rich at idle

[lx 1986]

I went to have my car smogged the other day and the mechanic told me that the car was running rich when it idles but when it's driven there is no problem. How do I fix this? The car runs great on the freeway and street as long as I don't come to a stop.

I've been trying to find an answer for this problem. When the car is warmed up and is in gear the idle drops when I step on the brake at a signal and the car feels like it's going to die. I have turned up the idle with the throttle stop screw and the car seems to run better but the problem is when I start the car in the morning the problem starts all over again. Of course I have continued to turn the throttle stop screw to compensate for the drop but all that does is the car runs hotter and then I have other issues that happen like overheating. I also noticed when the car is warmed up and the temp gauge goes up to about a 1/4 that when I put the car in park the idle will hang above 1000 rpms. Iv'e been adjusting the throttle stop up and down to try and compensate for the idle problem. I can't find any vacuum leaks and can't figure out what is wrong. Maybe someone else who's had this problem can help.


2bbl Keihin carb, 86 honda accord lx , auto, 2.0L

[Dr_Snooz]

How many miles?

[Lena01]

hello all, nice to meet you ALL HERE< 00

[Fixedit]

Ever find out a fix? Just started experiencing this when I parked at work. Idles rough and I can smell the exhaust and the cat getting hot

[Fixedit]

Info edit: 1987 DX
209K miles (if the dash is original. 5 speed swap wasn’t done by me and the dash has definitely been tampered with to cover up the PRND lights)

Got home and looked down the carb to see solid streams of fuel going down both barrels. Looked to me like the float was stuck up and fuel pressure was just shoving fuel straight through the carb. Just pulled off the top hat and cleaned quite a bit of dirt from the bowl. Been using non ethanol gas to clean things out so I expected a mess in there. Everything looked normal and operated freely (no sticking, just smooth movement and no fuel inside the float). Only now, with everything put back together, it idles rough but I don’t see the streams of fuel going into the carb. So that leads me to believe it is running rich only on the idle circuit, but I am unsure what to do about that. I’ve read that the mixture screw is blocked off from the factory as it isn’t necessary to adjust. What could be causing a rich idle circuit? My only thoughts are possibly an old gasket but I don’t know which gasket would affect only the idle circuit. The top hat gasket looked to be sealing everywhere just fine, and I cleaned off the mating surface on the carb body.

[Fixedit]

Car drives down the road beautifully, no hiccups at all. Just idles like crap and stinks up the cat. Idles better if I create a vacuum leak, but that just increases RPM rather than smooth the idle (confirming for me that it is getting too much fuel at idle). Don't know how to check the idle circuit system but I'll keep looking