Thats the choke pull off, yes you would need new one if it doesn't hold with a vacuum or when you depress and put finger on the hole. Once the engine starts, it is adjusted to pull on the choke (against the choke thermostat trying to keep close) as engine warms up. Then once warm, holds the choke plate open . . . As for the plugs, I would use them . . . can always take a wire brush to clean up a little bit, or if really concerned, file clean the center electrode and the ground electrode . . .