Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Vacuum Break (2GV Carbs.)
Press in on diaphragm plunger so that diaphragm is bottomed in housing and make certain choke valve is closed so that connecting rod is at end of slot in choke lever. Measure clearance between edge of choke valve and air horn wall (see table below). Adjust by bending connector rod (see Figure).
| Car & Carburetor | Choke Valve Clearance | |
|---|---|---|
| Buick | ||
| 70281 40, 41 | .120" | |
| 70291 40, 41 | .110" | |
| Chevrolet | ||
| 7028101, 3, 10, 12 | .100" | |
| 7029101, 3, 10, 12 | .100" | |
| 7029102, 4, 17, 18, 19, 20, 27, 29 | .215" | |
| 7029113, 14, 15, 16 | .200" | |
| Pontiac & Tempest | ||
| 7028060, 62 | .150" | |
| 7028066 | .170" | |
| 7028071 | .160" | |
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.