Yea, it may be worn out. When ever we try to get the last little bit of life outta a motor....like my old O.S. motor w/ pull start,you have to pull it fast....cuz if u pull it slow the air has enuff time to leak by and it wont start......(if it is worn out). Jus if u can after you run the car 4 a while and it shuts off.....turn the fly wheel over and see how well it hold compresion...if u can just sit there and easily spin the motor over with your finger its done....but if u have trouble turning it over and have to use a screw driver to get to turn over then its still good. Another way is if u still have pull start you should be able to pull the pull rope and the hole car should lift off the ground then turn over...if u pull the rope and it dosent budge then, yea its worn out.