return

Hi My boat is a sea ray 290 sundancer 1999 mod ther was orig. 2 x mercruiser 4,2 gas engines I have taken them out and instaled 1 Yanmar 6lp diesel 315 hp. I have a question : ther is 2 risers inn the fuel tank i am using on for diesel in and the other on for diesel in return, Butt i have a...