gas tank advice

A couple of days ago I filled my tank with fuel and a short time later the engine wouldn't run over 1100 rpms. I'd give it the gas and the engine appeared to be starving for fuel. The water separator had some junk in it and I traced the problem to the gas tank. My rig is a 87 cuddy with a 2001 150 Yamaha 2 stroke. I ran a portable tank of gas and the boat ran fine. I pulled the deck off ( which was a b#@&*) and found a INCA brand gas tank (60 gal) that I'm pretty sure is plastic and is original. My question is I have about 45 gallons of fuel and I think the line leading from the tank to the engine has some crap in it and does it have a screen attached to it. Any suggestions?