I have a 125cc quad that has always ran great but now it has a real hard time cranking. I've tried 3 different batteries and now a new one and it sometimes will roll over and sometimes just click, even with the 12v/10a Jump pack on it. I will say that my son was in some mud and when I removed the air filter there was some dirt in the inlet to the carb (this is a bad sign). Since this carb is sealed I can't truly take it apart for cleaning but I don't think that is my issue as it won't crank. If it does start, its immediately and it runs without issue so my questions is what to check next? In the past I've replaces wiring harnesses, rebuilt top ends on these, fixed busted transmission gears, swapped out lots of parts and such so where I'm going is I feel it has to be engine related. Like is the piston or something "stuck" inside due to possible dirt/rust? It has sat for a couple weeks and I'm just trying to troubleshoot before ripping into the top end and replacing the carb. Tuning a carb in Wisconsin fall/winter sucks and will most definitely have to be redone in spring. Its a 2021 with low hours so its not a tired engine and this problem happened right after the muddy ride... Should I roll it over by hand and then give the starter a try? I guess that one just came to me...

Any thoughts would be greatly appreciated.

DRN