That what I was thinking typical Tygon hose failure here and it is a fiction fit. Most small engine supply places should a supply of different size lines. Just depends on the size if you can get it in Nitrile rubber instead of that plasticize line. It also depend of the size of the nipples of the filter and the oil pump as to if you can up the size a tad and resize the through hole in the tank but you do want a snug fit.
Basically you cut a taper on the line thread some tag wire through the taper and twist tie it. With this assemble you feed the wire though the fill hole and out the line hole. Then you simple pull the line though to desired position. Sometimes you may need use pliers to get a hold on the taper as it exits the hole as you can pull the hold out of the line if the fit is a little over snug.
![[Linked Image from i.imgur.com]](https://i.imgur.com/Et6HKZk.png)