Ken, Your getting good advice so far. Here's my take;
Mixture setting
Float level
Your Float level is your first item for mixture setting. Consider it the
gross setting and the needle the fine setting. It's very important that the
floats are set to match each other, as close as possible. The gas is fed to
the throttle body by gravity. the old "Liquid seeks it's own level" rule is
the operable here. The level in the float chamber should be about an 8th of
an inch below the throttle body bridge. It's hard to check, but try this any
way. Take the domes off and the pistons out (don't mix them up) and shine
your flashlight down into the nozzle. (be sure to set the nozzles at the
same height) (all the way up is a good place to start). This may give you
an indication if one float level is out of whack from the other.
Needle and Nozzle Condition
Often the nozzle will get worn from a maladjusted nozzle or bent needle,
causing the nozzle orifice to become oval. This will manifest itself as a
too rich condition. New needles and nozzles are a good investment.
Needle placement
To seat your needles, raise the nozzles all the way up and loosen the needle
set screw and pull the needle out to where the needle shoulder is clearly
visible, below the piston body. Then, tighten the set screw till it's
dragging on the needle. replace the pistons back into the throttle bodies
and push them down. The nozzles will force the needles up into the proper
placement. Then, remove the pistons and tighten the set screws.
Needle - Nozzle Alignment
If the nozzle is not aligned in the center of the needle's path, all sorts
of crazy variables get thrown into trying to tune them. This is what the old
"clunk test" is about. There's an easy, sure way to do this and a tinker
around frustrating way.
The easy way involves buying an alignment tool. It's just an aluminum rod
sized on one end to the nozzle O.D. and the piston path in the dome chamber.
To use the tool you remove the piston (don't bend that needle!), unattach
the choke linkage on the bottom of the nozzles and pull them out (gas will
pour out of them), loosen the nozzle lock nut on the bottom of the throttle
body, insert the tool into the nozzle path, slide the domes over the other
end of the tool and tighten the dome screws down, Re-tighten the nozzle lock
nut, Then, pull out the tool and put it all back together. Sounds Easy?
NO!?!?
Or you can just loosen the nozzle lock nut, move it around, get it wrong, do
it again, make it worse, Do it some more ... and Again .. . over and over
and over and, if your lucky, you just might get it. I can't seem to
succeed in this method at all!
SU balancing is a whole different post all together, But I will say this
now, , , IT"S A HELL OF A LOT EASIER ON A 2 LITER THAN A 1600 !!! :-(
Victor
70 SRL311 13136
72 HLS30 94071
65 L-320 Pickup
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