Help adjusting rebuilt carb.

Printable View

03-03-2005, 02:52 PM
iron

Help adjusting rebuilt carb.

I've rebuilt and installed a carb on my 87 accord. It was not the originial carb. I bought a junkyard carb and rebuilt it. Original problem was car would idle high when cold (around 3k), and wouldn't kick down. It would also refuse to idle hot. Lastly it started bucking randomly. Now with the rebuild it idles at 3500 cold and when attempting to move the car under it's own power, it wants to red line the rpm. I ended up having to push the car to a level spot on the drive way to set the fuel level in the bowl.

I've read the threads dealing with setting the fuel mixture screw, but my car will not kick the fans on no matter how long it's run. I replaced the thermostat in the bottom of the radiator before doing the carb rebuild and it still wouldn't start the fans. I did try to put the AFM screw back in the same number of turns it took to take out when I rebuilt the carb, but I'm unsure how appropriate that is considering it wasn't the carb that came off the car.

I tested the fans by jumpering the thermo connecter and they do run. I've replaced almost every inch of vacuum line on the engine. Approx 50 feet. I've even redone the lines in the vacuum control box located on the fire wall.

It does sound a hell of a lot healthier than it did before, but I figure the mixture has to be out of whack along with the idle. I'm not sure if I should screw with the mixture or the idle first.

When letting the engine idle (about 10 mins) it seemed to be warm but the idle never dropped down. (Cold day it melted all the frost off the hood etc) Tapping the gas pedal had no effect, it would rev up a bit then drop back down to 3 grand.

To make things more interesting, this car has had a history of strange electrical problems. In trouble shooting the interior lights, I ended up replacing the fuse box under the hood and cleared up most of the issues the car had. (interior lights, door open indicators now work etc.) Any chance I may have a problem lurking in the interior fuse box? The rear defroster seems to still have issues so I know i haven't fixed everything on the electrical front. Anyone know if a bad fuse box would contribute to the engine idle issues?

Thanks in advance
03-03-2005, 05:23 PM
A20A1

Fix the idle first... you want the motor to at least be fully warm... if the fans don't kick in then give it your best guess... the reason I say set the idle first is because if the idle is too high you will be off of the idle circuit... then if you decide to adjust things like the mixture you wont be doing it right.

I'd say make sure things like the throttle cable, the thottle stop screw and idle diaphragms are all set correctly.

Vaccum leaks or a check valve installed in revers may cause the idle diaphragm to open the throttle and cause the car to red liine or go to around 4,000 to 6,000 rpm
I'm not refering to the cold idle.
03-03-2005, 10:01 PM
kilgorq

Quote:

Originally Posted by iron

I've rebuilt and installed a carb on my 87 accord. It was not the originial carb. I bought a junkyard carb and rebuilt it. Original problem was car would idle high when cold (around 3k), and wouldn't kick down. It would also refuse to idle hot. Lastly it started bucking randomly. Now with the rebuild it idles at 3500 cold and when attempting to move the car under it's own power, it wants to red line the rpm. I ended up having to push the car to a level spot on the drive way to set the fuel level in the bowl.

I've read the threads dealing with setting the fuel mixture screw, but my car will not kick the fans on no matter how long it's run. I replaced the thermostat in the bottom of the radiator before doing the carb rebuild and it still wouldn't start the fans. I did try to put the AFM screw back in the same number of turns it took to take out when I rebuilt the carb, but I'm unsure how appropriate that is considering it wasn't the carb that came off the car.

I tested the fans by jumpering the thermo connecter and they do run. I've replaced almost every inch of vacuum line on the engine. Approx 50 feet. I've even redone the lines in the vacuum control box located on the fire wall.

It does sound a hell of a lot healthier than it did before, but I figure the mixture has to be out of whack along with the idle. I'm not sure if I should screw with the mixture or the idle first.

When letting the engine idle (about 10 mins) it seemed to be warm but the idle never dropped down. (Cold day it melted all the frost off the hood etc) Tapping the gas pedal had no effect, it would rev up a bit then drop back down to 3 grand.

To make things more interesting, this car has had a history of strange electrical problems. In trouble shooting the interior lights, I ended up replacing the fuse box under the hood and cleared up most of the issues the car had. (interior lights, door open indicators now work etc.) Any chance I may have a problem lurking in the interior fuse box? The rear defroster seems to still have issues so I know i haven't fixed everything on the electrical front. Anyone know if a bad fuse box would contribute to the engine idle issues?

Thanks in advance

Is the butterfly on the choke opening? I had the same issue with mine and found that I had left the cotter pin to long and it was hanging up on the edge of the carb. I have also seen someone misalign the lever between the base and the choke causing it to not disengage fast idle.
03-11-2005, 02:35 PM
iron

Well the saga continues, I found I had a loose vacuum pot on the carb. It's the one front passenger side of the carb above the accelorator cable that opens the butterfly valve. It wasn't tightened down enough to keep it from bleeding vac. Fixed that and cranked the black handled idle screw down and got it to idle hot in spec. Now it's stalling when it kicks down. I haven't played with the mixture yet since I haven't gotten it to idle warm yet. Had to quit messing with it and haven't had a chance to fool with it yet, not willing to play with it in the freezing rain.
03-11-2005, 04:32 PM
A20A1

tightened down... you mean the choke puller body?
So the internal vacuum passage was leaking... k

The black knobed screw is the thorttle stop screw.
03-20-2005, 05:52 PM
iron

Quote:

Originally Posted by A20A1

tightened down... you mean the choke puller body?
So the internal vacuum passage was leaking... k

The black knobed screw is the thorttle stop screw.

Yeah I meant the choke puller. Yes I meant the throttle stop screw. It either idles too high or stalls no in between. I found a bad component in the vacuum control box too. I can't remember what it's called right now, it's connected to lines #5 and #15 though the manual is misprinted and calls them both #15 when giving trouble shooting steps. "remove #15 from the accumulator and attach vacuum pump, remove #15 from (whatever they called the metal vac tree) and attach vaccum gauge." Great instructions. :)

The component next to that one has a reference to 11-79 as the trouble shooting for it, too bad that page doesn't have anything to do with the specified component. This is the factory shop manual I'm using to beat it all. Must be a bad translation. Of course this is the same book that showed my fuse box to be oriented 180 degrees from what it is as well.

I'm just going to have to test every vac pot, vac switch and probably replace the evil box under the drivers seat as well since there's no straight forward check to see if it's working right or not.

Sigh