On Sat, 01 Jul 2006 12:55:16 -0400, Jeff Wisnia
wrote:

I've also seen small engine chokes which are closed by a spring when the
engine isn't running and opened by engine vacuum bled through a small
orifice to a rubber diaphragm which pulls the choke open against the
spring force. The orifice delays the choke's opening for a second or two
after the engine starts.

HTH,

Jeff

Speaking of orifices and not taking away from the OP. One Briggs I
have has a manual choke; choke - run. When rebuilding the carb once I
learned and cleaned these "tiny holes" with a wire from a wire brush
(stainless). It would not run or start until I cleaned these little
"vents" as I called them. Do not break off the wire..

Are these the orifices you mention? Along the carb tube, right at the
choke butterfly and very small like a wire I mention? I could never
get the proper term.

Oren