From the information about belts etc. being OK It seems that the starting capacitor on the motor is faulty or the centrifugal switch is faulty. The motor will not start under load conditions if the starting capacitor is not working. The centrifugal switch controls the starting capacitor, so if this is dirty or faulty the start capacitor will not be energised.

The centrifugal switch is inside the motor and you need to be quite skilled to attempt this repair.

The starting capacitor needs to be tested and needs special equipment. Be VERY careful if you attempt to remove the capacitor as it could still be charged and give you a nasty shock. Always discharge it using an insuated tool. From the information about belts etc. being OK It seems that the starting capacitor on the motor is faulty or the centrifugal switch is faulty. The motor will not start under load conditions if the starting capacitor is not working. The centrifugal switch controls the starting capacitor, so if this is dirty or faulty the start capacitor will not be energised. The centrifugal switch is inside the motor and you need to be quite skilled to attempt this repair. The starting capacitor needs to be tested and needs special equipment. Be VERY careful if you attempt to remove the capacitor as it could still be charged and give you a nasty shock. Always discharge it using an insuated tool.

If the belts and tensions are ok, then the problem seems to be the starting capacitor on the motor. If this capacitor is not in circuit, then the motor wil not start under load conditions.

The capacitor is controlled by a centrifugal switch inside the motor and you will need to dismantle the motor to repair it - this is a skilled job and should not be attempted unless you have done this before.

Of course the starting capacitor could be faulty. This will need checking with specialist equipment. If you do remove the capacitor be VERY careful because the capacitor may still have electrical charge on it and could give you a nasty shock. Always discharge the capacitor with an insulated handled tool. If the belts and tensions are ok, then the problem seems to be the starting capacitor on the motor. If this capacitor is not in circuit, then the motor wil not start under load conditions.
The capacitor is controlled by a centrifugal switch inside the motor and you will need to dismantle the motor to repair it - this is a skilled job and should not be attempted unless you have done this before.
Of course the starting capacitor could be faulty. This will need checking with specialist equipment. If you do remove the capacitor be VERY careful because the capacitor may still have electrical charge on it and could give you a nasty shock. Always discharge the capacitor with an insulated handled tool.