When using the single-vacuum distributor, the vacuum hose runs from the vacuum port on the left side of the carburetor to the vacuum canister on the distributor. In that case, the vacuum port on the rear of the carburetor must be plugged.
For most cool season grasses and for folks living in northern climates, the best time to plant grass is in late August, early September. Depending on exactly the climate you have and the type of grass seed you're planting.
CentipedeGrass.com - BEST TIME. The BEST time to plant centipede seed is in late spring / early fall after soil temperatures are 70+ degrees and all danger of freeze or frost is past. This generally takes 80+ consistent day highs in temperatures to achieve this temperature.