I have the following black and decker lawn mower ; cmm 1200 24 1 2008 10-49 last year I had to replace the part that contains the power port for the key and charger. The new part that is now on my mower, which has a start button on the side, will not accept the old key. Do I need a key for this new part. If so what is the part number? johnfthompson@gmail.com