Hi, recently I was using my nitro HPI rs4 as usual and there were no issues since the engine quits due to the wrong idle setting. Then I opened the throttle a little bit from the servo and pulled the rope to start it. 2 seconds after starting the engine locked. And when I got home, I saw that the engine was locked because of the 2 scratches on the liner and piston. There was no problem with the air filter or pin holder rings. Today I noticed that the pull start pressure spring is divided into 4 parts. Can it reach to piston from a hole on the crankshaft? What do you think could be the reason for this?

There should be a pin sticking out of the crankshaft. The spring pushes that pin against the pullstart shaft. Was the pin missing?

Pictures would be helpful.