When I set my thermostat to 70 the furnace ignites but the blower does not come on when I jump it up to 80 it works like it is suppose to what could be the problem?

It sounds like the thermostat is not allowing the burner to operate a long enough time to activate the blower. If your thermostat has a heat anticipator it may need to be adjusted. Look at the beginning of this board under stick notes.