Century V6-231 3.8L (1985)
Choke Pull-off: All Technical Service Bulletins
Engine - Poor Warm Up Performance/Hard Cold Start
Bulletin:
84-6C-12A
Date:
Feb. '85
Ref. No. 85-181-6C
SUBJECT:
CARBURETOR VACUUM BREAK TESTING PROCEDURE
MODELS AFFECTED: ALL CARBURETORS EQUIPPED WITH VACUUM BREAKS
NOTE:
This bulletin supersedes the original 84-6C-12. Please discard the previous bulletin and replace it with this one.
Hard starting or poor warm-up performance on a carbureted engine may be due to a leaking vacuum break unit. The vacuum break, sometimes called the
"choke pull-off", opens the carburetor choke valve against the tension of the thermostatic choke coil during cold engine start-up. A vacuum break unit
with a leaking diaphragm will not open the choke valve to the proper position, and may cause a cold engine to load up with fuel, resulting in black
exhaust smoke.
PLUGGING AIR BLEED HOLES
VACUUM BREAK TESTING PROCEDURE:
1.
Determine whether the vacuum break has a bleed orifice. If it does, it should be plugged as shown.. See Figure 1 for possible locations
^
Most rear or secondary side units have a bleed.
^
Most front or primary side units do not.