Hi all. New here and new to owning a quad. I have an '87 Big Bear 350. It has obviously seen some action, but has definitely been impeccably kept. Zero issues for me taking it out a few times, some decent miles hunting. My 15 year old took it out with buddies, having issues now of course. Dying out, like too much air coming in, backfiring, eventually wouldn't hardly start or run. Had manifold to carb replaced, one end was spinning in the rubber sleeve, so mechanic suspected air getting in. Seems somewhat better, but still having the issue to some extent. Compression good. Mechanic thinks maybe dirty/wet carb/fuel. I'm not so sure. Also seems to run hot easily. Oil cooler/radiator but no fan on this model. Any ideas?