Tune-Up Notes

IDLE SPEED ADJUSTMENT CAUTION: Procedures and specifications for idle speed adjustment must be followed exactly as outlined. See " Hot (Slow) Idle RPM " under Tune-Up .
1968 BUICK 400" & 430" ENGINES STALLING AFTER STARTING CORRECTION: Correct by changing "the Vacuum Break Setting to.180" (was.200"). See Rochester 4MV 4-Barrel Carburetor data for procedure .
NOTE: This change made in production on carburetors with change letter "A" (400" V8 engines). "B" (430" V8 engines)
1968 BUICK 400" & 430" ENGINES CARBURETOR PRODUCTION CHANGE & RECOMMENDED CHANGE TO CORRECT ENGINE FAILING TO START WHEN COLD: Caused by float needle sticking. On carburetors not previously modified (marked by daub of yellow paint on left side of throttle body). Install new larger float and new needle and seat assembly. See Rochester 4MV Carburetor data . Carburetors 7028246, 7028247, and 7048248, incorporate this change.
NOTE: For other items affecting Tune-Up, see Diagnosis, Testing & Trouble Shooting at rear of book and appropriate carburetor story in CARBURETION section.