1996 sportsman 500

Hello all! I just purchased a used 1996 sportsman. I did an oil change yesterday with 10-40 valvoline Syn wet clutch and an STP filter. Now I’m reading and it looks like I should use 0w-40. Should I drain and refil. Also what about the filter is that okay to use?
Also I’m now ready about pinching of the oil line to prime, is this necessary?

Thanks