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Thread: 78 civic hatch 1200 series: carb problems

  1. #1
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    78 civic hatch 1200 series: carb problems

    so im having carb problems with my civic. when ever i give her gas she back fires.. bought it from a co-worker and haven't done much to it. changed the sparkplugs (gaped right) changed the spark wires and cap (wires are right) had the timing done professionally. i no that the mechanic had to gap the points a bit larger then they shoulda been for some reason. noticed that the carb had no vacuum lines and everything was capped off. bought some tubes but with out a diagram i have no idea where to plug them into. also noticed that the carb has a leek in it.
    so basicaly i need a vacuum line diagram and a carb repair kit. would love a recommendation for a kit and some tips about stuff.
    anything will be appreciated =]

    heres a pic of the carb if it would help:
    http://tinypic.com/r/21ngmmg/7

  2. #2
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    Re: 78 civic hatch 1200 series: carb problems

    i have the same problem mines excatly the same way but it runs fine times adjusted up and one vac line hooked up..repair manual should show u how to hook it up..i got a NOS repair kit with gaskets for da carb just put one in..and my points were messed up bad...but got her runnin and got turn off now

  3. #3
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    Re: 78 civic hatch 1200 series: carb problems

    Back fires through the carb or exhaust are because a valve is still open during combustion. Recheck your timming and make sure a valve is not sticking.
    Switched plug wires could also result in this symptom. But a 4 cylinder would run rought as well.
    Excess gass in the exhaust could also result in an exhaust back fire. Engine would have to be hot.
    Does that carb have an anti backfire selenoid?

  4. #4
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    Re: 78 civic hatch 1200 series: carb problems

    Quote Originally Posted by 8803
    Back fires through the carb or exhaust are because a valve is still open during combustion. Recheck your timming and make sure a valve is not sticking.
    Switched plug wires could also result in this symptom. But a 4 cylinder would run rought as well.
    Excess gass in the exhaust could also result in an exhaust back fire. Engine would have to be hot.
    Does that carb have an anti backfire selenoid?
    couldn't tell you if the carb has an anit backfire selenoid, or if a valve is open. still new to this stuff so i kinda don't no what to look for.. =[

  5. #5
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    Re: 78 civic hatch 1200 series: carb problems

    Quote Originally Posted by loa706
    i have the same problem mines excatly the same way but it runs fine times adjusted up and one vac line hooked up..repair manual should show u how to hook it up..i got a NOS repair kit with gaskets for da carb just put one in..and my points were messed up bad...but got her runnin and got turn off now
    could you maybe send a pick of how you have the vac line set up. right now im running three from the carb to the: adv, retard, and throttle control. so the NOS kit fit well and did the trick?

  6. #6
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    Re: 78 civic hatch 1200 series: carb problems

    Is this a CVCC motor?

  7. #7
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    Re: 78 civic hatch 1200 series: carb problems

    Quote Originally Posted by 8803
    Is this a CVCC motor?
    no i don't think it is a cvcc motor.. the cars is a 1200 series witch i think is a step down from the cvcc's

  8. #8
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    Re: 78 civic hatch 1200 series: carb problems

    A bit more info. If it is a backfire into the exhaust there has to be air for the excess gas to explode. Again this is most likely related to timing in reference to things happening when the valves are open or a leak into the exhaust system. The most likely is again stuck valves and or a timing issue.

  9. #9
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    Re: 78 civic hatch 1200 series: carb problems

    Quote Originally Posted by 8803
    A bit more info. If it is a backfire into the exhaust there has to be air for the excess gas to explode. Again this is most likely related to timing in reference to things happening when the valves are open or a leak into the exhaust system. The most likely is again stuck valves and or a timing issue.
    pretty sure its not a timing prob. had the timing belt replaced and everything tuned. (cept the carb =/) as for it backfiring, when ever i give it gas the carb 'hickups' out the top. even had flames a few times >.>
    if theres any info that might be helpfull, let me no and i'll try my best to answer

  10. #10
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    Re: 78 civic hatch 1200 series: carb problems

    Think of timing in a more general way. If a motor is wired and tuned perfectly a mixture of fuel and air enter the cylinder with the intake valve open, both valves close and the piston is near or at top dead center, the spark plugs arcs and ignights the gas/air mixture dirving the piston down, than the exhaust valve opens and the spent gass is released. If during the firing stroke(powder stroke) the intake valve is still open(timing) or stuck open, part of the powder is leaked back up through the carb. This is what is happening. By timing I mean something is happening out of order, which is what timing really is. A backfire through the carb occurs because an intake valve is open when it should not be. It has to be miss a adjusted intake valve, a stuck intake valve or an intake valve open when it should not be open. Have your valves adjusted. This is a part of a good tune up. Be certin the plug wires are in the right place. If you recently had a timing belt replaced I would check to see all the marks line up.

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