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!!!Need help adjusting the air/fuel ratio on a carburated 83' RX7 GSL!!!!!


GSL Driver
07-10-2004, 01:36 PM
I Need to know how to adjust the air/fuel ratio on a carburated 83 RX7 GSL? I just bought this one about a week ago. This is my first one and it idles at about 500-600rpms. Which I think is low. Also I recently changed the clutch on it, and it runs threw 1st-3rd pretty good, but once I get into 4th and 5th it doesn't want to go past 4000 rpms for some reason. A friend told me the air/fuel ratio needed to be adjusted on it and we need to know how to set it cause it is a carburated motor. We don't want to mess with it until we know exatly what to do. So any hwlp would be appreciated!!!!!!

D3rELiC
07-10-2004, 04:26 PM
i'll start to mess arround with my two stock carbs once i understand em a bit more, but anyway, maybe this guy could help you, he use to rebuilt and modify stock nikki carb. nice buy BTW, the GSL are the only FB 12a with rear disk brakes and LSD.

http://www.sterlingmetalworks.com/racing_index.html

WV85RX7
07-11-2004, 01:44 PM
There are only 2 adjustments that can be made to the Nikki carb w/out disassembeling the top horn. The idle adjustment screw (located just left of and rear of the linkage assembly) and the idle mixture screw (located lower dead center on the carb main body.

If I remember correctly, clockwise on the idle mixture richens, counter leans. However- these adjustments only impact the idle circuit. It has no real bearing on the carbs performance when the primary circuits are running, accelerator pump/jet, or secondary jets.

I would imagine that your problem lies elsewhere. I would look at the following first:

Fuel filter- is it old? An old clogged fuel filter will sometimes flow enough fuel for idle and low speed but suffers at wot. You may be fuel starved.
Fuel pump? Is it flowing enough fuel? Check flow rates.
Cats- clogged cats can kill high end.
Coils- are you getting spark at higher throttle? That can kill high end.

Go to http://www.rx7club.com and get in the first gen section- Guys there will help you out.

If you find out the carb is the problem- Sterling is your man. He can rebuild and tune these carbs in his sleep.

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