?
"Oren" wrote

Agreed! I've _never_ seen a B&S engine that did not allow for
air/fuel mixture adjustment (since I was knee-high to a grasshopper).

Have you seen the newer engines? Many no longer have the two screws that
allow you to adjust the carb like days gone by.


From the Tecumseh manual, page 13 http://www.cpdonline.com/692509.pdf
A main or idle adjustment needle may be replaced by an
internally fixed jet on some models.
The main nozzle contains a ball check valve. The main
purpose of this ball check is to eliminate air being drawn
down the main nozzle during idle speeds and leaning the
idle mixture.