Hello all. i had recently bought a 1985 mazda rx-7, only 83k OG miles and pretty garage kept. I have just rebuilt the carb/ replaced the accelerator pump etc, and slapped it back on. Upon starting i notice that the car is idling at 2k rpms and when i try to give any gas the engine just cuts off completely. I'm thinking it could be the fuel air mixture or maybe even the idle screw but i'm not sure where to even start looking. If anyone has an idea of what it could be or where to start please let me know i'd be nothing less of appreciative

 

welcome to the board.

my first thought would usually be vacuum leak, but if it's fast-idling until you crack the throttle, then my mind goes to the mixture. maybe check both?

 

You can do the starter fluid test. . .. . Spray starting fluid into the carb while pulsing the gas pedal and see if you can get some high rpm's before dying.

If you can, it points to a situation where too much air relative to fuel is happening and you can't sustain combustion.. . . The car is getting to much air.. . . .Spray around the carb base and intake and see if you get a bump in RPM's. A raise in RPM's will signify a leak in that general location.

If you can't get the car to raise in RPM while spraying starting fluid into the carb, you probably do not have an air leak and it points more to carb issues or fuel supply issues.

And a high RPM is a symptom of too much air in my opinion. . . ..Or a carb plate is too open at idle.

General ideas . .hope it helps. .