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Discussion Starter #1
After 8 years of being a proud owner of an 83 280ZX I decided to get a second car as a project car. a '79 RX7, I got for $200 I painted it and fixed various little and bigger problems. the engine in it was a rebuilt '83 12A with 40000 miles on it. the car had 140 on it. I have to admit that although it is not a Z, yet it is more sporty and more fun to drive (not a car to go to work or be on the interstate though). To my surprise, it is as fast or even faster than the Z I got in certain situations. Probably cause it is a limited edition and weighted 200lb lighter thatn all the other RX7's.......and through the years I have modified the Z quite a lot (getting 0-60 in the low 7's with my normally aspirated engine).
recenlty I noticed that the rx7 smelled wich indicated that the fuel mixture was rich.
My 79 RX7 stinks when I drive it. I think the mixture is too rich, since there are no holes on
the exhaust, and you only smell it when you roll a window dow and have the sun roof open.
I know it has 2 screws on the carburator. The top controls the idle, and the other one the
mixture. I assume the top controls air flow.
I also assume the bottom control the fuel flow and has nothing to do with the air.
Is that true?
IF it is, would I need to turn it clock wise to make the mixture more lean?
If I do that for 2-3 turns, then the engine sounds rough on idling. should I then mess with the
idle screw again?
I turned the mixture anti-clockwise and it sounded better when the engine is warm 2-3 minutes
warm. But now it floods in the morning and I have to push it to start and of course a lot of smoke
comes out for about a minute.

PLEASE HELP !!! I am desperate and don't know what to do !!!
How do I adjust the mixture to be correct??
Thanx

ZAX Z
 

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Discussion Starter #2
Re: 280ZX & RX7 --- fuel mixture problems--HEL

> After 8 years of being a proud owner of an
> 83 280ZX I decided to get a second car as a
> project car. a '79 RX7, I got for $200 I
> painted it and fixed various little and
> bigger problems. the engine in it was a
> rebuilt '83 12A with 40000 miles on it. the
> car had 140 on it. I have to admit that
> although it is not a Z, yet it is more
> sporty and more fun to drive (not a car to
> go to work or be on the interstate though).
> To my surprise, it is as fast or even faster
> than the Z I got in certain situations.
> Probably cause it is a limited edition and
> weighted 200lb lighter thatn all the other
> RX7's.......and through the years I have
> modified the Z quite a lot (getting 0-60 in
> the low 7's with my normally aspirated
> engine).
> recenlty I noticed that the rx7 smelled wich
> indicated that the fuel mixture was rich.
> My 79 RX7 stinks when I drive it. I think
> the mixture is too rich, since there are no
> holes on
> the exhaust, and you only smell it when you
> roll a window dow and have the sun roof
> open.
> I know it has 2 screws on the carburator.
> The top controls the idle, and the other one
> the
> mixture. I assume the top controls air flow.
> I also assume the bottom control the fuel
> flow and has nothing to do with the air.
> Is that true?
> IF it is, would I need to turn it clock wise
> to make the mixture more lean?
> If I do that for 2-3 turns, then the engine
> sounds rough on idling. should I then mess
> with the
> idle screw again?
> I turned the mixture anti-clockwise and it
> sounded better when the engine is warm 2-3
> minutes
> warm. But now it floods in the morning and I
> have to push it to start and of course a lot
> of smoke
> comes out for about a minute.

> PLEASE HELP !!! I am desperate and don't
> know what to do !!!
> How do I adjust the mixture to be correct??
> Thanx

> ZAX Z
Does it have the hitachi four barrel?
 

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Discussion Starter #3
Re: 280ZX & RX7 --- fuel mixture problems--HEL

> Does it have the hitachi four barrel?
YES IT HAS A FOUR BARREL
 

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I also am having RX-7 troubles.

> Does it have the hitachi four barrel?

Hey, I've also got a Mazda giving me some problems right now. It's idling very rough, and it's hard to kee it running. It acts like it is straving for air.

It's got the four barrel carb on it. I'v heard that these carbs rarly go wrong, but I would like a way to check it if you know of one. I have read every manual that I can find, and they still don't tell me of a starting point for the mixture screws. I have the carb that is not the california maodel, so I can get to both screws. (The california models have the bottom screw covered with a cap that needs a special tool to remove it.)

Any help that you can provide will be appreciated.
 

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Discussion Starter #5
Re: RX/7 hitachi four barrel

> Hey, I've also got a Mazda giving me some
> problems right now. It's idling very rough,
> and it's hard to kee it running. It acts
> like it is straving for air.

> It's got the four barrel carb on it. I'v
> heard that these carbs rarly go wrong, but I
> would like a way to check it if you know of
> one. I have read every manual that I can
> find, and they still don't tell me of a
> starting point for the mixture screws. I
> have the carb that is not the california
> maodel, so I can get to both screws. (The
> california models have the bottom screw
> covered with a cap that needs a special tool
> to remove it.)

> Any help that you can provide will be
> appreciated.
Ok, it's been a few years but
IF you haven't messed with the bottom screw, you set the idle speed with the top(large) screw.
It's a bypass adjustment for the idle circuit,your controlling the flow with this screw.
Now if you have messed with the lower screw you have to work the upper and lower in steps to get your best idle quality, back out the lower(mixture) screw a turn or so then adjust the upper out until the speed picks up where it should be. then turn the lower in until it falters a little. then backout about 1/8 of a turn, go back to the top screw and adjust it until you get the correct speed again.
And so on until it drives/runs right for your liking.
Please don't tell me you turned the screw for the butterfly adjustment(throttle position).
to set that you need to take the carb. off the car and measure the angle of the throttle plate with a protractor
centered on the throttle shaft.
and that angle is different for each application(year,man.,auto)
The best way to set these carbs
is on a gas analyzer (of course)
but the above proceedures work well.

I used to be a 13/B guy and really enjoyed the rotary engines.
I know a guy out here with a 10 second rx/7,race only,ports tuned, pipe tuned, turbo.

Hope this helped you out!
 
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