Tom M's flat spot

["Robert N. Deruy" <bobxian@domain.elided>]

Remembering my old dual weber days; a transitional flat spot is sometimes
associated with too lean an idle mixture. The accelerator pump has too much
wark to do to keep the mixture at a reasonable level.

I've been amazed at the nuber of times the "overcarburation" problem is
made worse by trying to "lean out" the carb.

Just a thought. (Uh, SCCA days were a long time ago, I could have this all
wrong, but that turned out to be the problem with the j**p, it ran better
at high altitudes)

Tom how does it feel going over the pass to Missoula?

Bob (can't fix his own scout so he's full of ideas for others) Deruy

>It sounds like you have a "flat spot" in the transition from the idle
>circuit to the main metering circuit.  As you know, when the throttle is
>opened the air moves faster than the fuel which causes a momentary lean air
>/ fuel mixture condition, and of course the accelerator pump is supposed to
>bridge this gap.  You have been playing around with the accelerator pump I
>know, so this is baffling.  Have you tried an accelerator pump cam and
>setting which gives immediate and a long dispensing of fuel?  You probably
>don't need a huge volume of fuel... just an immediate and sustained amount
>until the main metering circuit can catch up.