Thanks for your response!
Yes, the replacement capacitor was new, purchased from a local motor repair shop and it has same ratings as the old one.
The impeller is almost the exact part, the only noticeable difference in size is the overall diameter of the new impeller being ~1/4 in smaller on the new impeller.
When I run the pump in high speed, it works in a similar way as the old impeller (similar flow of water through the jets). When I have the heater on and I run the pump for 10-20 sec several times in high speed, it eventually switches to low speed when turning the high speed off.
I just tried to help spin start the pump by hand and couldn't do it so I suspect the impeller might be jammed/pressed in the wet end. I ran the motor without the wet end assembly with no problem but did not run it with the dry wet end assembly on. Guess I should have...
I will try to run it dry and if it doesn't work will look at a different impeller or whole wet end assembly.