Carburetor - New Float Level Gauges
Number: 84-194Section: 6 (VIM)
Date: Sept., 1984
Subject: NEW FLOAT LEVEL GAUGE FOR DUALJET AND QUADRAJET CARBURETORS
Model and Year: ALL WITH DUALJET AND QUADRAJET CARBURETORS
TO: ALL CHEVROLET DEALERS
FIGURE 1 - QUADRAJET/DUALJET FLOAT LEVEL GAUGES:
Enclosed are three (3) new external float level gauges, as shown in Figure 1, for checking the float level in all current Quadrajet and Dualjet carburetors.
The new gauge, P/N J-34935-1 or BT-8420A, reflects the design variables of the past several years that may have led to occasional inconsistent readings when the older gage was used. The new gage is also suitable for checking the float level of all past model quadrajet and dualjet models, and in checking mixture control solenoid plunger travel.
Figure 2 - External Checking of Float Level:
The procedure for external checking of Float Level has not changed (see Figure 2).
Figure 2 - External Checking of Float Level:
1. WITH ENGINE IDLING AND CHOKE WIDE OPEN, INSERT GAGE IN VENT SLOT OR VENT HOLE. ALLOW GAGE TO FLOAT FREELY.
NOTICE: DO NOT PRESS DOWN ON GAGE. FLOODING OR FLOAT DAMAGE COULD RESULT.
2. OBSERVE THE MARK ON GAGE THAT LINES UP WITH TOP OF CASTING. SETTING SHOULD BE WITHIN +/- 2/32" (1.588 mm) OF SPECIFIED FLOAT LEVEL SETTING.
INCORRECT FUEL PRESSURE WILL ADVERSELY AFFECT FUEL LEVEL.
3. IF NOT WITHIN SPECIFICATION, REMOVE AIR HORN AND ADJUST FLOAT.
Figure 3 - Checking Mixture Control Solenoid Plunger Travel:
The procedure for checking Mixture Control Solenoid Plunger Travel on E4MC, E4ME, E2MC, and E2ME models has not changed, and is outlined in Figure 3.
Figure 3 - Checking Mixture Control Solenoid Plunger Travel:
1. PLACE J-34935-1 OR BT-8420A IN "D" SHAPED VENT HOLE. ALLOW
GAGE TO TOUCH SOLENOID PLUNGER.
2. OBSERVE MARK ON GAGE THAT LINES
UP WITH CASTING.
3. PUSH GAGE DOWN UNTIL PLUNGER IS IN "DOWN" POSITION, AND OBSERVE DIFFERENCE IN GAGE READINGS. THE SOLENOID PLUNGER TRAVEL SHOULD BE BETWEEN 2/32" AND 6/32".
The new gauge replaces J-9789-130 or BT-7720, which should be discarded and should no longer be used.