recently given an old fourwheeler. old carb was gunked out beyond cleaning. I bought a new oem one. now it idles way too high. I'm not an expert on atv repair. When I first started it up with the new carb on, it idled awesome, then it started to climb revs until it was too scary to leave it running. if i put my hand over the air intake side, it dies, but if i close the choke, it climbs. i can get it to idle normally for a bit, but when it starts to climb revs it wont come back down by itself, i have to partially cover the air intake with my hand and keep it there. on the air intake side, there are two holes i assume are vent holes? if i cover them, it climbs. no idea what to do.