Mine is in an experimental as well, so I'll see if I can find more info
on getting or making some sort of mixture control...thanks for the info!

Scott


wrote:

On Dec 12, 5:03 am, Scott wrote:

OK, so us poor bastages with A-65s with no mixture control might be
screwed anyways Anybody have any ideas on how to get a mixture
control onto an A-65? If I recall, my carb is an NAS3A1 Stromberg. I
THINK there might be a plate on top of the carb where a mixture control
may have been present at one time???


That's it. Finding the bits and pieces might be a hassle. I
made mine, since it's a homebuilt, and it works OK. It's a back-
suction type of mixture control, where the lever rotates a valve under
that cover. There's a hole into the float bowl, another into the dead
airspace behind the venturi, and another into the venturi itself. The
area behind the venturi is at roughly atmospheric pressure, and the
venturi, of course, is much lower than that. The mixture control
valve, when rotated toward "Lean," gradually shuts off that port to
the dead airspace, allowing the venturi port to start sucking against
the fuel in the bowl. That decreases the differential pressures at the
fuel nozzle and flow decreases.
It won't work as an idle cutoff. There's so little flow through
the venturi at idle that nothing happens when you pull the mixture all
the way out. Carbs with idle cutoff are using a valve inside the carb
that varies the flow of the fuel itself from the main jet in the
bottom of the bowl, so that if it's pulled full lean, all flow,
including idle fuel, stops.

Dan

--
Scott
http://corbenflyer.tripod.com/
Gotta Fly or Gonna Die
Building RV-4 (Super Slow Build Version)