Keith,
My two cents worth! First, you are not going to be able to tell much
about your jetting with free load testing. Was this carburetor on this
size motor before? If so I can't believe that it is too far off.
Carburetors have a great flexibility because fuel is delivery is
dependent upon the velocity thru the carburetor venturi. Carburetors
will adjust somewhat even to the larger displacements.
As far the leaning at high idle, this is a common problem with
carburetors. This is called a transfer problem. There are three systems
to be considered in the carburetor fuel delivery system, the idle
circuit, the main circuit and the power circuit. As the throttle opening
increases, at approximately 1000 to 1500 RPMs, the major fuel control is
transferred from the idle to the main circuit. If the idle system is a
little lean, then there is a lean condition, flat spot, or a complete
failure to run, depending on how lean the idle circuit is.
Assuming a correct fuel level in the carburetor, on production vehicles
my approach for correcting this is by drilling the idle jet a couple of
thousandth. Raising the float level slightly will also usually solve the
problem, but this also richens up the other systems, as well, which
probably isn't a big problem with what we do. Good Luck!
Tom, Redding CA - #216 D/CC
Keith Turk wrote:
>
> Well the Headers were Much Cooler this Morning and I wasn't Falling down
> tired....
>
> Everyone's Comments about it being Lean seem to Point in the Right
> Direction.
>
> The Plugs were Toasty... Not White... but Lean.... Now the question is Why
> does this Carb start Running Lean at a High Idle.
>
> This is about our Favorite Carb... an Old 750 Holley that has really served
> us well over the last two Years. It's been worked on a Ton... and Flows
> really well and for the Most Part has been really Predictable. We have run
> it on 4 different Motors From a Dead Stock 300hp 350 to the D motor at
> Bville.
>
> Kinda enjoying sitting here and Listening to everyone's Comments....
> Thanks..
>
> Keith Turk
> Austin Healey 100, Bugeye, Box sprites, Bonneville Camaro ( Land Speed
> Racer)
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