You sure can but try replacing the small fan start capacitor first. They go bad and won't start the fan more times than the fan motor goes bad.
If the old unit was a 10 SEER or less. If the old indoor coil has an expansion valve you should be fine but if it has an orifice type metering device then it should be replaced
The outdoor unit only runs in the AC mode(unless it is a heat pump). If you have the system off and the fan on, the outdoor unit should not be on. You can run the indoor fan only without harming the system.
The electric motor is probably bad if only the fan is not working. If you cannot hear the compressor running, either, then you may just have a tripped breaker, or the relay on the outside unit may be dirty. Ants like to get in those outside housings for the electronics; it's good shelter. The relay can be cleaned, and the breaker reset. If the motor is bad, it can be replaced. Call your local A/C service company.
Is the whole unit running or just the fan? My thermostat has the option to run the fan only at all times and also runs the fan when the temperature gets too high (or low) in the house.
No the out side fan is for venting heat away fromt he unit.
yes
The outside AC unit fan may not be turning on due to issues such as a faulty motor, a broken fan blade, a malfunctioning capacitor, or a tripped circuit breaker. It is recommended to contact a professional HVAC technician to diagnose and repair the problem.
The coils on the outside AC unit may be frozen due to restricted airflow, low refrigerant levels, or a malfunctioning fan.
The fan motor in an outside AC unit helps to circulate air over the condenser coils, which helps to release heat from the refrigerant and cool down the air that is being blown into your home.
For an internal fan motor... I just paid right at around $400 to have ours replaced. Or if you replace it yourself. You be looking at only 50 to 100 dollars and not rocket science.
A fan clutch can't be tightened, just needs to be replaced.
The outside AC unit fan motor is responsible for circulating air over the condenser coils to help release heat from the refrigerant, allowing the air conditioning system to cool the indoor space effectively.