Hi Folks, Brian here from south Africa. I have a 1982 Rx7. The accelerator system stopped working. The carb has never been opened since I've owned this great little car (some 30 years) so the first step was to get rid of all the accumulated gunge.
Question 1: The only exploded view of the carb I've ever found shows a weight and check ball below the screw above the accelerator pump housing, which is supposed to function as a one-way valve. My carb does not have this, but only a screw with a horizontal hole opposite a very small intake from the float chamber.
at the base of the screw is another small hole which provides direct access to the working side of the pump diaphragm. This means that gas can flow back into the float chamber as the pump is activated.
Am I correct in assuming that although some is lost back into the float chamber, most fuel is pumped through to the nozzles in the carb intakes as this is simply the path of least resistance, the intake hole being that much smaller than the output? Does anyone else have this modification to the weight and check ball or is mine an original design which was changed later?
Question 2 : The brass weight below the injector nozzles has frozen in place, blocking the passage of fuel when the pump is operated. I have put penetrating oil into the the threaded hole above the frozen weight and left it for 24 hrs, but no dice. I have tried pushing compressed air into the hard-to-get-to hole on the side of the diaphragm chamber (which feeds the nozzles) but can't get a good seal. Didn't work either! Any advice would be appreciated.
Thanks,
Brian Duckitt

 

The problem with the sticky weight has been solved. I sharpened a small screwdriver to a flat knife edge and with lots of gentle tapping made a small slot in the top of the weights (stel being stronger than brass!).
This enabled me to rotate the weight at the bottom of the threaded hole and work the weight loose. A touch of compressed air at the intake passage and out she came!
If anyone knows the answer to my question (1) I'd still appreciate and answer.
Brian RSA

 

Not sure about your exact question but I would make sure that the diaphragm isn't torn. It's a soft part and now is really old. I had one torn once and couldn't tell until I got it out of the carb but I am just speaking generally. Never owned an FB.

 

Yup the diaphragm is fine. Apart from the stuck weight in the one way valve below the fuel injectors above the primary barrels (that problem solved) I also found that the VERY small holes in the injector were clogged. These have been cleared and I'm now getting fuel squirted into the twin primary throats when I push on the activating arm of the pump.
My first question was as follows:
Question 1: The only exploded view of the carb I've ever found shows a weight and check ball below the screw above the accelerator pump housing, which is supposed to function as a one-way valve. My carb does not have this, but only a screw with a horizontal hole opposite a very small intake from the float chamber.
at the base of the screw is another small hole which provides direct access to the working side of the pump diaphragm. This means that gas can flow back into the float chamber as the pump is activated.
Am I correct in assuming that although some is lost back into the float chamber, most fuel is pumped through to the nozzles in the carb intakes as this is simply the path of least resistance, the intake hole being that much smaller than the output? Does anyone else have this modification to the weight and check ball or is mine an original design which was changed later?
Cheers,
Brian