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 Post subject: 78 civic hatch 1200 series: carb problems
PostPosted: Sun Jul 17, 2011 2:55 am 

Joined: Thu Jul 14, 2011 11:56 pm
Posts: 24
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


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 Post subject: Re: 78 civic hatch 1200 series: carb problems
PostPosted: Sun Jul 17, 2011 6:49 am 

Joined: Fri Jul 08, 2011 8:03 pm
Posts: 21
Location: Georgia
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


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 Post subject: Re: 78 civic hatch 1200 series: carb problems
PostPosted: Sun Jul 17, 2011 8:55 am 
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Joined: Fri Mar 25, 2011 9:24 pm
Posts: 100
Location: Monrovia CA
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?


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 Post subject: Re: 78 civic hatch 1200 series: carb problems
PostPosted: Sun Jul 17, 2011 7:40 pm 

Joined: Thu Jul 14, 2011 11:56 pm
Posts: 24
8803 wrote:
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.. =[


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 Post subject: Re: 78 civic hatch 1200 series: carb problems
PostPosted: Sun Jul 17, 2011 7:43 pm 

Joined: Thu Jul 14, 2011 11:56 pm
Posts: 24
loa706 wrote:
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?


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 Post subject: Re: 78 civic hatch 1200 series: carb problems
PostPosted: Mon Jul 18, 2011 7:13 am 
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Joined: Fri Mar 25, 2011 9:24 pm
Posts: 100
Location: Monrovia CA
Is this a CVCC motor?


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 Post subject: Re: 78 civic hatch 1200 series: carb problems
PostPosted: Tue Jul 19, 2011 1:10 pm 

Joined: Thu Jul 14, 2011 11:56 pm
Posts: 24
8803 wrote:
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


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 Post subject: Re: 78 civic hatch 1200 series: carb problems
PostPosted: Tue Jul 19, 2011 7:44 pm 
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Joined: Fri Mar 25, 2011 9:24 pm
Posts: 100
Location: Monrovia CA
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.


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 Post subject: Re: 78 civic hatch 1200 series: carb problems
PostPosted: Wed Jul 20, 2011 2:53 am 

Joined: Thu Jul 14, 2011 11:56 pm
Posts: 24
8803 wrote:
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


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 Post subject: Re: 78 civic hatch 1200 series: carb problems
PostPosted: Wed Jul 20, 2011 8:07 am 
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Joined: Fri Mar 25, 2011 9:24 pm
Posts: 100
Location: Monrovia CA
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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 Post subject: Re: 78 civic hatch 1200 series: carb problems
PostPosted: Wed Jul 20, 2011 1:59 pm 

Joined: Thu Jul 14, 2011 11:56 pm
Posts: 24
8803 wrote:
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.

ooooooh okay. i see what your getting at now. now im sure that the wires are right, and that the all the marks are inline (was there watching the hole time) basically we did everything but touch the carb. so if the valves need to be adj, were are they located on the carb?


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 Post subject: Re: 78 civic hatch 1200 series: carb problems
PostPosted: Thu Jul 21, 2011 8:25 pm 
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Joined: Fri Mar 25, 2011 9:24 pm
Posts: 100
Location: Monrovia CA
The valves are in the head ( intake and exhaust). Not the carb. Maybe this is a job for a mechanic, but you could do it your self. Watch a few Youtube vids, get a manual for the car and you will need a basic set of metric tools and a feeler gage. Check out honda sights and maybe find a real service manual for free.
You need to wrench crank the engine over to put each piston at top dead center and see if there is the correct gap in the rocker arm to valve. If there isn't this means the valve is not fully closing and that is the problem.
A valve can also be sticking open so you need to check that all the valves open and close completely.
Get fimiliar with the process and than watch a mechanic do it. Maybe?


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 Post subject: Re: 78 civic hatch 1200 series: carb problems
PostPosted: Fri Jul 22, 2011 2:10 pm 

Joined: Thu Jul 14, 2011 11:56 pm
Posts: 24
8803 wrote:
The valves are in the head ( intake and exhaust). Not the carb. Maybe this is a job for a mechanic, but you could do it your self. Watch a few Youtube vids, get a manual for the car and you will need a basic set of metric tools and a feeler gage. Check out honda sights and maybe find a real service manual for free.
You need to wrench crank the engine over to put each piston at top dead center and see if there is the correct gap in the rocker arm to valve. If there isn't this means the valve is not fully closing and that is the problem.
A valve can also be sticking open so you need to check that all the valves open and close completely.
Get fimiliar with the process and than watch a mechanic do it. Maybe?


think that would be the best way to go about it. watch a few vids and a mechanic then try things out.


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