Can;t get gas up to carb

Well, I removed the sending unit. All was ok, blew air thru. It was fine. Blew air thru the fuel line, all ok. set vacumn pump on line drawed gas up to fuel pump. still not the greatest. fuel filter barely fills up. I believe the return line is plugged. I am going to look at that next. There is a rubber line under the passenger seat. that may be rotted or collapsed. i will keep everyone posted.