This is the direction correction not engaging properly and there are a few possible causes. The pump prefers to spin backwards, path of least resistance, if it does so the prop flies forward and hits the front cover and falls back spinning the right way and then syncs up with the electromagnet coil and runs in the right direction. Causes of this failing are as follows in order of probability.
1) Propeller is damaged by wave maker use or otherwise, if the prop ends are damaged or it is not engaged to the propeller magnet it needs to be replaced. The same symptoms will occur if the wrong propeller is used, for example one from a 6055 or 6015.
2) On the 6045 if the blue flow adjustment tube is cocked or jammed by a foreign object it will hit this instead of the stops and get stuck, remove the blue tube, rinse the black housing and blue tube and check for any debris and reassemble. Make sure the parts are properly engaged so the blue adjustment tab is in the slot on the black piece.
3) The stops on the front housing were damaged by an attempted modification, if the front crosshatch is removed or modified the direction correction is removed as well.
4) The voltage is wrong or frequency, if the pump is from another country, it will not likely work properly, the motor is different for each voltage/frequency and cannot be reliably compensated by travel adapters or transformers. Likewise UPS systems can cause problems with pump starting though an already started pump will continue to run. To start properly a US/Canada model 115V 60Hz pump needs 102-132V and will have some trouble/delayed starting and chattering outside a range of 105-130V.
I bought the impeller after the first one broke it has never worked since replacing it. I have tried the bushing in every configeration it still knocks
The propeller is brand new. I think it might be the wrong impeler but i dont know for sure what the packaging said on it I threw it away long time ago
Try this, take it out, hold the magnet portion in one hand and turn the propeller with the other, it should turn freely about 270 degrees each way before hitting a stop, the AC versions need to start the magnet turning before the blade, the DC version won't have this. If it does not have the free play it is the wrong one and is for a 6055.
I would contact Xenia, the troubleshooting should be fairly simple trial and error, my main thought is something is wrong with the impeller assembly or possibly the disk at the bottom of the shaft fell out at some point. It could be line voltage if this was a fairly old house or the circuit was overloaded.