White Knight eco 83a only turning in one direction. new motor fitted?

I have a white Knight eco 83a.

The motor struggled to turn so I ordered a new motor and it arrived today. I have fitted the new motor (I am an electrician but not an appliance repairer) and the new capacitor. When I start it up it used to rotate one way, then the other, and then the first way with the gas ignited. Now however it turns one way, stops and then ignites the gas for a few moments. I expect it then shuts the gas off because the motor isn't running. After doing a google search it would appear that it could be the capacitor and the new one is dented. I have tried it with the old one and it still does the same thing. Any ideas? Thank you.