E-B-27
PARTS-SERVICE
January 20, 1991
S70-155XL,
H70-155XL
GRAM
Carburetion
Subject: Carburetor Icing
The G.M. 4.3 liter V-6 engine equipped with gasoline carburetor is prone to icing under certain atmospheric
conditions.
To assist in combatting this condition reinforced graphite gaskets for the carburetor and governor are
available. These gaskets will transfer heat from the intake manifold thru the governor into the carburetor
base. In conjunction with these gaskets an insulating sleeve is available to install over the automatic choke
heat tube.
Service Engineering recommends if icing is encountered or the carburetor is removed for any reason all
three of these improved parts be installed rather than the original gaskets.
1331032
Insulating
Sleeve
1328937
Graphite Gasket
1328936
Graphite Gasket
We reserve the right to make changes in design or add improvements without incur-
ring the obligation to make such changes in equipment previously manufactured.
H6030
E-B-27
Page 2
Installation Instruction:
Remove carburetor and governor as a unit. Separate the carburetor from the governor being careful not be
damage tube P/N 368241 and  O ring P/N 370299, if installed. Clean gasket surface on carburetor,
governor, and intake manifold. Remove steel heat tube P/N 352989 between manifold and carburetor
choke housing. Slide insulating sleeve P/N 1331032 over tube before reinstalling. Install graphite
gasket P/N 1328936 on intake manifold and P/N 1328937 graphite gasket between carburetor and
governor. Reset automatic choke bimetal coil from index position to three notches lean for additional help.
Interchangeability:
Parts are directly interchangeable.
Parts Stock:
Factory built units will continue to be produced with original style composition gaskets. Improved gaskets
should be stocked.
Effective Serial Number:
N/A