What do you rinse the tank with...fresh gas?
Yeah.
Not so much of a problem in lawn mowers since they have plastic tanks but gas will still "gel up".
Plus water, dirt, impurities......
Just pop line off. Usually just a clamp you press together with pliers.
Drain. Put your finger over hole and put a bit of gas in, swish and drain.
Might want to look at filter too.
Mine wouldn't start this spring because it was run dry last use. Filter hardened up, all crusty with gunk.
I just put rubbing alcohol in a few times and cleaned it out. Not very professional but worked for a really old, not maintained POS mower I didnt want to spend money on.....
FYI - Craftsman has owners manuals online. Should have all the basic maintenance and trouble shooting guides in it.
If not, you can go to sears website customer support and they will send you a PDF.