[FLZman]

It shouldn't but since it got louder and now won't start is possibly/probably because there isnt enough compression to draw fuel. Pull the plug and verify that somehow you don't have a hole in top of piston. You will probably need a flashlight to see down in there. There will be a little "pit" but make sure it hasnt gone through the piston. If not, inspect the engine very closely, possibly with magnifying glass if you have one and look for any crack or leakage signs. Only one thing can cause a lost of compression, that is not having a sealed engine or at least sealed to factory design.