Mixture Control Solenoid Stop Screw

With solenoid lean mixture screw properly adjusted and air horn installed, install Float Gauge (J-34935-1 or BT-8420-A) in air horn vent hole. Allow float gauge to contact mixture control solenoid plunger. See Fig 1 . Note line indicated with top of air horn casting.
Press downward on float gauge and note indicator mark. Release float gauge. This difference between the indicator lines is the solenoid plunger travel.
Using Stop Screw Adjuster (J-28696-10 or BT-7928), turn rich mixture stop screw until total solenoid travel equals 4/32" (3.17 mm).
After adjustment, install lean mixture screw plug and rich mixture stop screw plug. Plugs must be installed at specified location to seal settings and to prevent fuel vapor loss. See Fig 2 .

Fig 1: Adjusting Mixture Control Solenoid Stop Screw

Courtesy of GENERAL MOTORS CORP.

Fig 2: Installing Lean Mixture Screw Plug & Solenoid Stop Screw Plug

Courtesy of GENERAL MOTORS CORP.