Volvo Penta model 2003-T: what size diesel supply and return line tank nipples to order?

[Sue F]

I bot a one-off sailing cat with 2 44-hp Pentas and flexible Nauta fuel tanks. Tanks are old and seeping, so am ordering replacement tanks. My boat is in Mexico and I cannot inspect the system. They offer drawing nipples with 1/4, 1/2 or 5/8 inch barbs. I have no idea what size to order, but would guess the 1/2". Would anyone be able to offer a recommendation?

 

[alldodge]

The threads are NPT (national pipe thread)
Meaning, 1/4 NPT means it has a 1/4 inch inside hole

Being only 44HP I would expect a 1/4

Normal is 3/8 for larger motors, and that said, without measuring