This mower is ten years old and works fine except for this glitch. When I go to start it the starter doesn't engage immediately, it goes zzzzt and then nothing in which case I let off the key and turn it again, or it goes zzzzt and then turns the mower over. Most times I have to turn the key to start and then back several times before I can get the engine started. Two or three years ago I took the mower in to the local Gravely dealer and they fiddled with it for a week, and replaced the stator and some other electrical parts and still could not get it fixed to where it starts like it did when new. What do I need to do to fix this thing? All of the terminals including the battery connections are clean and brite.