Ken, when you push up the plunger, yes, you do disable that carb. Because the
butterfly or throttle plate is closed, there is almost no vacuum on that
outboard side of the carb to pull the fuel up. When you do this you are
checking
the mix IN THE OTHER CARB, NOT THE ONE YOU ARE DISABLING. The car should still
run, but act like it is on 2 cylinders (which it pretty much is). When you
first
push it up, it will rev up for just a second, then run rough. If it dies, the
other carb is too lean. If it does not increase slightly at first, it is
probably too rich. Adjust the mix on the other carb until it is as close as you
can get. Then, do the opposite to the next carb in just the same manner. Make
sure first that your carbs are balanced (i.e. flowing the same amount of air at
idle... so that the butterflies are open the same amount). If they are not
balanced, you cannot accurately set the fuel mix. Use a Unisyn or other carb
balancing tool (available at JC Whitney... a good one really, or at a VW bug
parts supply house or maybe a few speed shops). Trying to do it by ear takes
practice, and is still not that accurate. The one on JCW does not require any
skill to use, as you can leave it in the carb without pulling down the idle like
with the Unisyn. With the Unisyn, you have to practice putting it on the carb,
reading it, and taking it off really quick or you don't get an accurate reading.
Hope this helps!
Greg Burrows
Ken Pearce wrote:
> Two questions:
>
> 1.)I've been told, and I believe it's in the various reference manuals that
> lifting the piston of the carb with your finger effectively disables that
> carb. Doesn't this take the needle completely out of the jet and leave it
> wide open? Or is it too open and therefore not have enough air pressure to
> suck fuel in?
>
> 2.)When I turn my mixture adjustment all the way lean on this carb, the car
> will still run on that carb alone. In an effort to further lean it out, I'm
> adjusting the needle so that it sticks out further from the piston, about
> 1/16". Will this help me lean it out further or am I barking up he wrong
> tree?
>
> Thanks,
>
> Ken Pearce 68-2000
> Bellingham, WA
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