I have had 2 different diagnosis from 2 different mechanics for issues of black smoke and high idling with my Honda Civic 93, DB15 engine with twin carby, manual, AC.

I have lost my faith in mechanics and I would like to know opinions on what I should do. Should I fix it myself??? I have already replaced the fan switch, O2 sensor and have had a major service done.

The car blows black smoke, even after a major service. Once warmed up, it would idle at 1800-2100 and the black smoke usually disappears. The black smoke is due to a fuel and air mixture issue which results in my car only getting 300-340klms per full tank, than before where it use to get 480-550klms per full tank. I presume this is due to the high idle and fuel mixture/black smoke issue.

It struggles to stay idle at less than 1600rpm, so when I first start the car in the morning, I would have to drive it around till it gets warmed up otherwise it dies or otherwise, I have to rev the car when at a stop at about 1800rpm for it to remain running.

1st Mechanic diagnosis-
sticky choke
valves need adjusting to fix black smoke

2nd Mechanic
Carby requires overhauling
Choke/Wax pellet not working
Power vale fault(I presume its a mistype and should say valve)
Vacuum leak from carby intake rubbers

I tend to believe the 2nd mechanic since they were recommended by a close friend who has been going to the same mechanic for over 10 years.

Are the faults listed from the 2nd mechanic DIY'able? Would I be better off buying a used twin carby or engine? What are my possible options because I have spent almost 4K on this car on repairs alone and I have only had it for a few years!! Now I have to spend more!!! I could have spent for a later model car at the start if I had known this car would have had so much issues!

Any help, opinions or advice appreciated.

 

not many mechanics know how to work on carbs ... you would probly have better luck going to a old school muscle car shop lol, were they still use cars and know how to tune em ... sounds like you just have a loose screw or something dumb that fell apart in the carb. IMO you would just switch over to a d16 with, direct port injection from a yard .. or you can do a b swap if you want more power.

 

You're running crazy rich.
Edit: If you feel up to it you can rebuild the carb yourself. There are a LOT of small parts so keep that in mind. Otherwise send it to the second mechanic. You could search a junkyard for a used one but that could be hit or miss.

 

rebuild your carbs, im 22 and know carbs, its a shame noone knows how to work on them. it could be as simple as adjusting your mixture screws and leaning it out a little bit.

 

I think my carby is computer controlled?? That is why I changed my O2 sensor to help fix the fuel and air mixture which sort of worked at the start and now it is back to black smoke again.

 

i would unhook all the computer junk and run the carbs manual. im not sure how honda carbs are, but my old 86 f150 inline 6 had a computer controlled carb. i pulled all those wires right out of there, wired the electric choke to a potentiometer, and called it a day.