decelerating popping

["Stella Chia" <stelc@xxxxxxxxxxxxxxxxxxxx>]

Regan,

I have experienced this popping but in my experience, it was because I have
set the idle mixture too lean and then opening the trottle too much to
compensate.  I believe this causes rich unburnt mixture (from the carb's
primary circuits) to be sucked (from high decelerating vacuum) out into the
exhaust due to the too open trottle.  The idle circuit should not allow
unburnt fuel to detonate in the exhaust.

Once the idle mixture is right, my Alfa never pops on deceleration no matter
how rich a main jet I use.

My humble opinion only.  Other digester may want to throw more light.

Andrew C

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