The impeller might need lubrication or to be replace.
- Check the engine water inlet.
- Check the water inlet valves (main drain and skimmer) to be open.
The noise might come from the engine vibration. You will need to solidify the engine to the floor or place something under the engine to put a stop to this vibration.
Bubbles out of jets
- Check if the water supply to the motor is sealed (air noise at shutdown).
- Make sure the water level is at 2/3 of the skimmer.
- Check the pump O-Ring robbers.
- Check the skimmer flap.
- Check if the skimmer and pump baskets are free of debris and in their proper position.
- Check for cracks and replace pipe if necessary.
- Add more Teflon on cracks than on the screw caps.
- Check the O-Ring rubbers.
- Add lube or replace if broken.