On Sat, 6 Sep 2008 20:54:22 -0700 (PDT), "Robert M. Gary"
wrote:

On Sep 6, 9:58*am, Tman x@x wrote:

I think I'm going to follow a new SOP. *Turn the carb heat off on
mid-final. *Reasoning: no carb, esp a warm one is going to ice up in 30
seconds, sets me up better for a go-around, and will prevent this
stumble business (I did test it out at altitude, and it prevents or at
least seriously mitigates the stumble).

Don't put any money on that bet. I've had carbs freeze up on me during
stop-n-goes from the time it takes to kick off the heat to the time it
takes to pour on the coals. The carb can freeze in seconds.

-Robert, CFII

I'm with you Bob.
I once thought I'd throttle back and poke under some mist and pop out
the other side and resume. when the power came off the revs started
dropping and dropping and dropping. I bunged on full carb heat and
then full throttle and still the revs kept dropping. out the corner of
the eye I noticed a shaft of sunlight and turned toward the hole in
the mist. about 2 seconds into the sunlight and I had full power back
again. when it happens it happens quickly.

now back to the op's description of a rev drop on opening the
throttle.
my bet is that the carb has been in service for quite a while and the
leather bucket seal on the accelerator pump is knackered. it isnt
giving the full squirt of fuel on acceleration. the other possibility
is that the little jet pipe has moved out of the centre venturi
position and the squirt isnt making it up into the inlet tubing.
far better me thinks that he doesnt wank on creating new procedures
and gets the a&p's to check the carby functioning.

Stealth Pilot