My lawn mower will not start, acts as if the battery is dead but i replace battery. If i jump it starts but then when i go to engage blades they will not cut on. Seem like its not getting the power to engage them? I left jumper cables connected and engaged the blades, they came on fine. Was able to to run after i disconnected cables and cut grass for awhile. After i cut the blades off they wouldn't come back on? I have to jump it everytime w jumper cables to start it or engage the blades.