GMC 1989 Light Duty Truck, Repair Manual, Page: 618 / 998

6C2-20 MODEL M4MEF CARBURETOR
1. REMOVE AIR HORN, GASKET, POWER PISTON AND
METERING ROD ASSEMBLY, AND FLOAT BOWL
INSERT.
2. ATTACH J-3 4 8 1 7 -1 OR B T -82 2 7 A -1 TO FLOAT BOWL.
3. PLACE J-3 4 8 1 7 -3 OR B T -8 2 2 7 A IN BASE WITH
CONTACT PIN RESTING ON OUTER EDGE OF
FLOAT LEVER.
4. MEASURE DISTANCE FROM TOP OF CASTING TO TOP
OF FLOAT, AT POINT 3/16" FROM LARGE END OF
FLOAT. USE J-9789-90 OR BT-8037.
5. IF MORE THAN ± 2 /3 2 ” FROM SPECIFICATION,
USE J-3 4 8 1 7 -2 5 OR B T -8427 TO BEND LEVER
UP OR DOWN. REMOVE BENDING TOOL
AND MEASURE, REPEATING UNTIL
WITHIN SPECIFICATION.
6. CHECK FLOAT ALIGNMENT.
7. REASSEMBLE CARBURETOR.
J-3 4 8 1 7 -1
OR
B T -8 2 2 7 A-1
F-01925
Figure 40 - Float A d justm ent
J-9 7 8 9 -9 0
or
B T -8 0 3 7
______ C ZL
1 .
2
.
3.
4.
M ake su re th e p u m p lin k is in th e s p e c ifie d hole.
W ith th e fa s t id le cam o ff th e cam fo llo w e r lever, tu rn th e th ro ttle s to p sc re w o u t so it d o e s n ot to u c h
th e th ro ttle lever.
M easure th e d is ta n c e fro m th e to p o f th e c h o k e valve w all to th e to p o f th e p u m p s te m .
A d ju s t, if necessary, by s u p p o rtin g th e p u m p lever at S and bending at the notch. F-04367
Figure 41 - P um p A d ju s tm e n t