carb running rich

[Whistler225]

Hello folks. I've been reading through the different posts on various carb issues, and have one also. I just bought an 86 LX from my boss (for 100 bucks). Drove the car home, and had to put my foot to the floor at each stop light to keep it running. Got home, found the choke spring was disengaged, so I fixed that. Now the choke opens, but the car idles extremely high, and rich (I smell gas while driving and my tailpipe is black). I've tried adjusting the float screw, and the idle screw (kind of a pain to get to, isn't it?) and it seems like I'll get the idle right, but then after awhile, the problem will return.
I'll be replacing the following tomorrow:
fuel filters
engine coolant (with flush)
air filter
possibly the carb gaskets since the thing is hissing like mad when the air cleaner is off
I've checked all the vaccuum lines and they seem ok. I'm reluctant to replace them since they are numbered.
I know the a/f mixture screw could be adjusted, or it could be a waterlogged float. I was just wondering if anyone else out there had this specific problem and might be able to save me a bit of money/diagnostic time here.
Oh, and the car acts a little like it's still choked when I take off. I know the choke is opening....I've checked it about a thousand times already.
I can tell this will be a great little car once I get everything squared away. I just don't want to melt my Cat running it too rich. I would also like to avoid messing with the A/F if possible....Dad always told me to leave that damned screw alone unless I had tried everything else already. Plus, taking the carb off to get to it looks like it might kind of suck.
Oh, and does anyone know if there's any way to tell for sure if the motor mounts are bad, or if the wierd idle is causing my car to shake at the stop lights?
Thanks for any help you guys can give me. I'll be doing a few things to this car and will try to post pics.....
Dan

[A20A1]

Don't mess with the a/f screw... it's ment to be tamper proof... if you find it is leaking or dislodged then you can try to fix it... chances are you wont need to touch it.

1) Fix any vacuum leaks, gaskets, hoses, PCV valve.

2) Change both off the fuel filters.

3) Then check the float again. Problem is the float adjustment screw is very prone to leaks if adjusted, even with month old o-rings... both internal and external leaks so it's not always visable.

4) Try to set the idle as low as possible when the car is fully warm and move up from there.
http://www.3geez.com/forum/showthread.php?t=46572

5) Readjust the float level if it changes.

[Whistler225]

A20A:

Thanks....I've seen your posts all over this board. You seem to know your stuff.

Funny thing....I did tweak the float level a little bit again last night, and it seemed to improve a little bit. I got in it this morning, went through the usual begging it to start (I live in NH, so even spring mornings are chilly), drove it to the gas station and filled it up with 89, and walla! It ran AWESOME all morning on the way to work. It even seemed to behave better at stops in gear. Idle is still a wee bit high, but I'm going to be doing the stuff you mentioned in your post later today, and re-adjusting the idle as well as that cable that runs to the transmission (I get downshift at odd times on the freeway).

One thing I noticed about that idle screw: it seems to take alot of turns for it to have much effect. Of course, being so hard to get to, I can only give it about half a turn at a time.

[Whistler225]

oh, did I mention this car sat in a backyard for an undetermined period of time? ;-) Sorry about that.

[A20A1]

you have to lower all the other idle screws and be sure there are no vacuum leaks tripping up the idle diaphragm causing it to raise the idle more then it should. When the other idle screws are no longer holding the idle speed, then you can adjust the black knob (throttle stop screw).

You might want to check your trans fluid... also the tighter the cable is on the trans, the more likely it will be to stay, or shift into a lower gear. The looser it is, the quicker it will up shift gears.

[Whistler225]

well, I did half of what you're talking about with the idle screws before coming inside and reading your post. I have noticed it seems like all the vacuum lines are the originals (i.e. they have the numbers on them), so I guess it would behoove me to just go ahead and replace them....I can read the vacuum diagram if I need to in the future.

I was disappointed to find that the carb rebuild kit isn't readily available from the local auto parts store. one thing I would like to eliminate as a problem is a vacuum leak in the carb... the bottom gasket looks ok, but the one between the middle and the top hat looks a little ragged. I pulled the top off the carb earlier and the gasket looks whole, but old. The float seemed to move freely and wasn't heavy, so I think it's ok....

still running rich....it's gotta be the float adjustment, but I can't see the damned level through the window. I've tried to get at it to clean it....any tips? also, which direction on the adjustment screw to make the mixture leaner?

thanks for all your help....I know you'd probably rather be out playing with your own car than answering my stupid questions. It's my first Honda, so this is kind of baptism by fire for me.....:rocket:

[A20A1]

you turn the A/F screw in to lean the mixture... out to richen it... out is counterclockwise.

There are 2 screws holding the float bowl window to the side of the carb body... I would only mess with it with the carb off though.

[A20A1]

actually, I was asking about the float adjustment screw. I guess I ought to be able to clean the window with a q-tip, and get it readjusted. I didn't realize this screw really has nothing to do with the mixture. Hey, thanks for all your help.....I'm going to do all the maintenance stuff this weekend....including radiator flush etc.....if I can't get the idle right, I might try reaplcing the thermo valve next

oops, I missed that sorry... yeah you turn it in/down to lean the mixture some, and raising it will richen the mixture... it's best to keep the level centered and not try to raise it or lower it past that.

[Whistler225]

I'll let you know how it all goes....

[Whistler225]

well, I've tinkered with the idle quite a bit now, and here is what seems to be going on:

I'll get it down to where it should be, and it will be fine for the next drive. The next time I start it (if it's still warm), the rpms will be a bit higher than they were when I parked it. Each subsequent start, the rpms are higher. It doesn't make sense to me, but could it be a gas-logged float?

I'll be rebuilding the carb as soon as I can get the kit. Messing with the idle seems to have helped, i.e. the car is running better now than when I bought it, but I just can't get the idle to stay put. I've noticed that the high idle doesn't seem to kick in when I start the car (I have to nurse the idle until it warms up enough to run on its own), so I was also wondering if the valve that controls the high idle circuit works both ways (engage/disengage), or if it's two separate controls, one to engage, one to disengage?

It drives great....no apparent loss of compression. It does run a bit warm sometimes, but I still have to do the flush on the radiator. Out of curiosity, does this particular year require the special Honda brand coolant, or will the regular green stuff do?

[Whistler225]

well, just in case you're still watching this thread, I've adjusted about as much as I can, and the idle seems to have settled at about 2k in park, 1k in gear. I guess this is about as good as I can expect until I get the carb rebuild kit and replace all the vacuum lines, gaskets, etc.

I did adjust that transmission cable (the one that controls shifting) today, and boy, what a difference! The car drove pretty well before....now it drives AWESOME. Upshifts are crisp, downshifts are on demand. It seems hard to believe this car only puts out just under 100 hp.

As I mentioned before, I only gave 100 dollars for the car. It passed inspection today. It is in really great shape for the price/age. I'll see if I can upload some photos when I get them.

Thanks for your help

[Whistler225]

I know this thread is old....Lost: I have a question about the air door on the air cleaner. I think I "iced" my carb the other day (it felt like I was trying to drive through my parking brake, but the engine and tranny were behaving normally....just couldn't make the car go more than 20 mph), and I think it's because my air door isn't working or the tube that provides air from the exhaust is missing. I assume the exhaust tube comes off the air cleaner right under and behind where the air door is and runs to somewhere (on the exhaust manifold?) to get warm air when the car is cold. Can you give me some clues on how to figure out how to troubleshoot this? I know it should be simple, but as this is my first Honda, I'm trying not to assume anything. The car doesn't warm up very well, and I think putting in this tube for warm air might help.

I also have another (probably minor) issue. I can't get the idle to settle. I've adjusted that black screw several times. It seems like any time I park the car, if I start it again before the car cools down, the idle jumps 500-1000 rpm in park. (it idles at 2k in park the first time out right now).

[lostforawhile]

yea thats probably carb icing,if the engine is warm and it sits for a few minutes does it act normal again? by the time you get the air cleaner off the ice in the carb throat is already melted from residual heat. it'll act like it's not getting gas even if you put your foot to the floor. it uses three systems the hot air system,the coolant flowing through the intake manifold,and the efi heater which is under the base of the carb(electric heater). there should be a hose from the little tube off the side of the exaust manifold to the small metal tube under the air cleaner snorkel. with the engine cold you should be able to feel vaccume at the air door motor,also you need to check that air door to see if it is holding vaccume. I haven't found one yet at a junkyard that holds vaccume. majestic honda has the air door motor for about 20 bucks plus shipping. as far as the idle first check for vaccume leaks,then you might want to search through some of the threads in carb tech since there are a number of reasons for this,also if the air door motor is leaking vaccume that could cause idle problems.

[Cant Stop]

i use central auto parts here in florida they are affiliated with auto value parts stores so try to find one near you.

i just called my store and they have two kits available without a carb part number i dont which one you need but they are in stock, one is 52.39 and the other is $40.59 plus tax, our tax is 6.5% if you need me to get you one let me know and i can get it.
and this includes o-rings for the float adjustment screw.

[Acid X]

Hmm. I'd like to know more about this transmission cable adjustment. My car shifts fine, but sometimes it wont shift down when i stomp on the gas. Or it will take a little bit..

Hm. And i'll get that kit out asap whistler..

[parker09]

I have an 86 lx manual transmission. When I start it in the morning. The choke slowly kicks on until it gets about 3000 rpm. And while doing that it smokes black, until I kick it down and idles fine. It has a little hesitation when in low rpms but after 2500 rpm it runs fine. Also smells really rich while drive. It almost feels like the car isn't breathing well when I start it. Then after the choke is done it seems to run really good unless I try to hammer the gas in low rpms. Any ideas?

[parker09]

you turn the A/F screw in to lean the mixture... out to richen it... out is counterclockwise.

There are 2 screws holding the float bowl window to the side of the carb body... I would only mess with it with the carb off though.

I have 86 Honda accord lx its a manual trans. When it start it it takes awile for the choke to kick on and it will slowly rise to about 3k but it will smoke black until then. After that I kick it down and idles fine. When I try to hammer the gas it has a little hesitation in low rpms. 2500 rpm and up runs great but it smells really rich. And ideas or feedback?