RX7Elmo

Hello rotary fans. I've been out of the rotary scene for a while after the motor in my FD3S blew up on me. Anywho, i just purchased an 83 FB with only 55K miles on it.

the only mechanical issue with it currently is that it surges (very slightly) under constant throttle (coasting at say 40mph).

I saw the FAQ about surging with the SE models (EFI) but nothing about carb models. Anyone have ideas what it could be before I checked around? Loose hose in the rats nest?

Currently, the surging is bad enough that It won't pass smog as it can't maintain a constant RPM on the dyno.

Thanks

rotarygod

iTrader: (1)

It sounds like it is running lean.

RX7Elmo

that sounds about right actually, i never stopped to thinkn about the fuel mixture. Are the carbs on these things slightly adjustable with an air/fuel mixture screw to compensate?

Zyrano

see this post with pictures =)

https://www.rx7club.com/1st-generation-specific-1979-1985-18/i-need-know-idle-control-screw-mixture-screw-381065/

RX7Elmo

thanks zyrano, it seems that just changes the mixture below 2000rpm or so. i guess to change the mixture past that i'd need to redo the jets. would some techron carb cleaner help?

RX7Elmo

k, i did more searching, and it seems like the sputter valve is a prime candidate.