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.
Cool-season grasses are best established in the late summer or early fall. It is important to apply the seed using the correct seeding rate. The appropriate seeding rate is generally listed on the bag of seed. The grass seed is generally seeded on the surface and then lightly raked into the soil. The smaller the seed, the shallower it should be planted. Very small seeds like creeping bentgrass will need to be very close to the surface, whereas larger seeds like tall fescue can emerge from depths of 0.5 to 1.0 inch.