'87 Civic 1500 carburetor problems

[mark1974]

This is long and maybe way more info than needed. If you don't know a lot about these carburated nightmares you should probably just skip this. First some car history. The car was originally a daily driver and driven until the timing belt broke at I think 80 some thousand. My uncle picked it up and fixed the head and gave it to my dad. It smoked pretty bad on start up. We knew it had been driven short trips so figured the rings were stuck. I treated the oil and gas many times with different things including ATF but nothing worked. Also right after getting it from my uncle it didn't have much power so I started working on it. I found the timing belt was off a tooth so fixed that and adjusted the timing. I messed around with the carb many times for little problems including putting a kit in. Time passes and one day it starts missing. I heard it crank and right away knew it had a low cylinder and knew it would be major to fix so didn't even check it out. My dad kept driving it and it just got worse to the point it would hardly start. It was blowing clouds of smoke and would hardly get out of its own way. He finally parked it. I told him it wasn't worth fixing so it was going to be hauled off. It sat there for over a year then fuel prices went crazy so I come along with the bright idea (or not so much) to check it out and maybe fix (no labor cost) and drive myself as it would be cheaper than using my Dodge Cummins as a daily driver. I pulled the head (only 117k on car at this point) and found #3 and 4 exhaust valves burned pretty badly. I had the head fixed and popped in new rings and rod bearings. The oil rings were so stuck that the pistons would drop right back in. Got it running with yet another carb kit because the accelerator pump diaphragm was leaking. Also found the vac advance was bad and the thermal valve for the secondary was bad. What burned the valves? I'm not sure. Possible timing issues in the past or improper valve last or running too lean? Those are my guesses and I hope I'm not repeating something. I can wipe some soot out of pipe yet the plugs are white clean. Replaced the o2 sensor some time back as the old one didn't test right. Okay so I have put about 6k miles on the thing in a year and it has been pretty good with no more oil consumption to speak of. The problem is I have a hesitation that comes and goes. It will fall flat for a second when I first hit the go peddle. The pump is working. For quite some time now it has not been doing it bad at all. Yesterday I did a bunch of tune up stuff (valves, timing, clean dist. and cap, check/gap plugs) and after I put all back and drive off its doing the hesitation thing again and pretty badly. Its hard to work on because it usually doesn't do it when I'm in running the throttle by hand where I can watch stuff. Back when I fist got it going again I accidentally adjusted the screw on the aux. barrel butterfly thinking it was the idle. It didn't have the hesitation when my dad was driving it. I figured this must be the problem so I played with this adjustment in and out many times but it never really fixed it. I didn't even touch that this time. I have a Honda book and it says nothing about this adjustment so I have no idea where to set it. I really don't know what this aux. throat in the carb does either. Does it feed the aux. valves? So many vacuum valves and lines in this car its insane. The japs had a serous nightmare when they thought up this semi electronic feedback system. So many parts that can fail and cause all sorts of strange problems that are very hard to track down. I have carefully searched for vacuum leaks and replaced some hoses. The machine shop failed to clean the EGR passage in the head. It was/is fully plugged due to the bad rings/valves. Problem is I didn't realize this until way later after I had been driving it for some time. So the EGR system is completely non function. Could this have any affect? Another problem is that when its semi cold and I take off down the road it doesn't like to decelerate when shifting. It will just keep reving at whatever RPM it was at when I shift. It will come down slowly if I leave my foot off the peddle. Even when warm it is a little slower than it should be to slow down it seems. I have lubed the linkages and choke and everything moves freely. It also has a new throttle cable as I broke the old one. Another problem is the choke is less than perfect. I can set it and it will start up but then want to die unless I flutter it a bit and then it will level off at its high idle. I don't care so much about this. Idle speed is also a bit touchy. If I set it to the book spec its just too slow and dies real easy when taking off or if lights/fan are turned on and yes the idle up solenoid is working but might not be adjusted perfectly. I'm thinking something in the idle circuit is a little less than perfect. I did clean the carb good when I went through it although I didn't soak it. Its all this external stuff that screws with my head even when I have a Honda book. Wish I had a parts car so I could throw stuff at it and see what happens. I have already put more into the thing than its worth. Bottom line is if anyone could help me with the hesitation problem and adjusting of the aux butterfly that would be great. I just wish I could afford a newer EFI car and get away from this craziness. Mark

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[mark1974]

Well right out of the shop this last time it had the bad hesitation thing but the next day it was fine. I sure don't understand what it is when all I did was remove the air cleaner and put it back after doing the engine tune up work. Its been running pretty well all this week so I dunno. I realize this is way too complex to try to get answers long distance and there probably aren't many people around who really understand these older carburated cars.