Hello, my fiesta starting become more strange behavior than I was bought it.

Normally my car starting up complete about 2 sec (0 rpm to idle rpm), but now it would do 0 rpm to about 500 rpm for few sec then back to idle rpm, that happen sometime (not all time) today. It give me worry because I thought my starter motor being struggle starting due bush worn? Anyone known that problem before?

My theory;

If starter motor, inside have bush to contact motor to allow flywheel spin to being start the engine but they starting worn and losing connect, which that mean flywheel become struggle to spin because starter motor spin slower than idea speed flywheel?

I'm sorry but the translation is poor and I (and probably others reading) can't really understand what you are saying