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.
Seeds germinate when soil temperatures are above 65 degrees F. Sow the grass seed in early spring through late summer, earlier is better. Harmonize with seasonal rains. If you want to get a head start on preparation, consider planting a cover crop in the fall. (See below for more details.) Preparation.