The rotor arm is inside the dizzy cap, when you take the dizzy cap off, you'll see a red/brown kind of coloured plastic bit, it's like a 'T' shaped piece with 1 screw through the middle to hold it in place.
Probably not the route to your problems, but worth a change over nonetheless I should imagine.
Furthermore regarding the mapping side to things, I'd contact mike and explain the situation as it could be something to do with the map/fuel side of things, as suggested by Daniel.