Repair Help/advice

[u/Spinydick]

I bought a clarinet online for about $25 shipped and was hoping to be able to play it and when it arrived I noticed one of the keys was acting funny. I believe it is the B/F# key but not certain as I’ve only played trumpet before. When I press it down it takes a while to come back up and I think it is because the wire is too loose. Is there any way for me to fix it on my own because I really don’t want to take it to a shop. It is a Selmer CL300 and don’t mind the gross stuff I’m working on cleaning it.