My car has been running really poorly since I got it running and I found out why - when you look into the carb at idle, one throat you can see the gas squirting pretty constantly, but the other one jsut occasionally spits fuel. Is this the float needle causing this? There is plenty of fuel in the bowl

 

yep the needle could have crap on it.
and not be seating..
i have had this problem was a mixture of crap on my needle and inproper float adjustment's

if your carb hasnt been rebuilt in a long time the rubber tips can shrink..

 

What is the difference in float needles between the FBs? On Mazdatrix, it says for 81-82 and 83-85...I have an 82 carb float needle jsut lying around...but if it doesnt match....

 

HA! Answered my own question...they are SO different...is it the screen down there on the plastic part that was filthy?

 

screen??
maybe you should consider to rebuild it

autozone has the gp soreson kit
i have used it 3 times and awsome results each time..
comes with more bits than any other rebuild kit i have seen...

are you up to the task?

 

At the end of the float needle there is a filter(screen) and then there is a plastic tip afterwards. Mazdatrix shows the part that I have minus that plastic tip on their carb parts page.
I got this car non running and got it started before doing anything to the carb. Once I got it to run(it idled ok but the accel diaphram was shot and the secondaries were stuck shut), I took the carb apart and regasketed the whole thing (Victoria British kit) - since everything but the accel pump diaphram and secondaries were working correctly, I didnt do a full rebuild. I guess I can go get the kit and just rebuild the whole thing. Does that kit come w/ the float needles?

 

yep on the float neddle's