The unisyn is amust for multi carb set ups. It is a vacume gage that sits on
top of the carb. To adjust the carbs with the unisyn you free up the linkage
and use the throtle stop screws until each carb reads the same then
retighten linkage . Check again at idle and check also off idle. Sometimes
with carbs that have worn throtle shafts you have to adjust the carbs off
idle cause one will want to open sooner than another. You should be able to
find a unisyn at motorcycle shops. they are around 20 bucks and a must have
tool IMHO. You can also adjust idle mix with vac gage hooked to manifold,
adjust until you get the highest reading. I like to run mine just a tad rich
at idle. BTW I am running 3 1-brl strombergs with .050 jets in the front two
and a .049 in the rear carb. Do you have California Bills Chevrolet GMC &
buick speed manual. Good source of info. Here is another good source that I
feel is well explained.
http://home.inreach.com/geewhiz/carb.htm
Print out carb tuning the scientific way and keep for future reading. I have
to read things about ten times until it finally sinks in. Remember that with
any multi carb (high perf) set ups everything has to be just right or it
will lead to total failure.
Eric Johnson
Vista,Ca (San Diego)
48'Carryall w/56'GMC 270
49'Carryall w/Rust
oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
|