Enclosed are three new External Float Level Gages that have recently been released for checking the float level in all current Dualjet and Quadrajet carburetors. See Figure 1.
The new gage, part no. J-34935-1 or BT-8420A, reflects the design variables of the past several years that 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 Dualjet and Quadrajet models, and in checking Mixture Control Solenoid plunger travel.
The procedure for external checking of the float level has not changed. See Figure 2.
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.
The new gage replaces J-9789-130 or BT-7720, which should be discarded and SHOULD NO LONGER BE USED.
General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.