New to site and need help. I’ve searched thru other posts and have not found exact problem. I have an 03 660 that has had some backfire issues and seemed to be running a little rich. I pulled carb bowl and cleaned the best I could although it look spotless. Put back together. I also adjusted fuel air screw. Put all the way in and backed out to 2 1/2. Quad starts and idles good but I’ve lost power and top end speed. Only gets up to about 30 mph. Need suggestions on what to look for that would cause this issue. I have not messed with anything else.