I have a Sportsman 400 2004 and put new carb on it and rpms surge at idle, anyone have idea? Put new pump on and hoses ran correct, new fuel filter, having to keep adjusting idle screw. Did see hairline crack on carb to manifold boot but it’s on outside by the bolt but will change shortly. Have adjusted throttle and carb at the top adjusting screw. One more question and that is that it can be ran and warmed up but if I turn off then almost immediately turn back on I have to have choke out again. I am a auto/ diesel technician but want advice from someone that is familiar with these issues. Thanks in advance.