At what temperature should idle mixture adjustments be made in Stormberg NA-R9B float-type carburetor?


The temp is nominally 68F, but the acceptable range is 40 to 80 ambient, by practice.

I can't say about that specific carb, but generally in the Stromberg and the SUs, there is a needle, which can be raised and lowered, which changed the metering. By changing the taper of the needle, you can also change the mixture profile through the venturi flow rates.

We used to use a manometer to get the vac reading, and then look at EGT to make a decision on mixture.

The needle height will impact the overall mixture, and the shape of the needle will impact the mixture through the flow range.

What aircarft is this on? I know some of the J-3s had Stromberg carbs, but this specific carb model is not ringing any bells on aircraft.

  • 1
    $\begingroup$ Are you sure you aren't looking at a NA-R9B??? $\endgroup$ – mongo Apr 30 '17 at 20:21
  • $\begingroup$ My bad, it is NA-R9B. "B" looked like 8 on my paper. Sorry about that. $\endgroup$ – Kevin Castro May 1 '17 at 0:29
  • $\begingroup$ Kevin, there are sources for the maintenance manual for this carb. If it is on a plane that will be flown, someone should have the manual. Try this place: timetravelair.com/techlibrary/EO%2015-10BA-2.pdf $\endgroup$ – mongo May 1 '17 at 0:46
  • $\begingroup$ ALSO, looking at the above referenced manual, this is not a variable venturi carb, which I initially thought it was. So disregard my talk about the needles for mixture adjustment. At least we now know the correct carb, and have a manual for it. Sorry it took a little to get there. $\endgroup$ – mongo May 1 '17 at 0:48
  • $\begingroup$ Is okay. Appreciate for the help. Really need it for the verbal. $\endgroup$ – Kevin Castro May 1 '17 at 0:57

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