Fuel Tank Question

[Bierkan]

I have a plastic ~30 gal fuel tank that came with the truck that I'd like to re-use. It's in decent shape and is clean (verified by looking at the gas we poured out of it).

We've mounted it between the frame rails already but I'm confused has to how a filler neck is supposed to attach to it.

The original building used a 2" to 1-3/4" adapter hose to connect the filler neck to the tank. It leaked badly. It also appears cut at an angle for some odd reason. There wasn't a clearance issue the way it was set up.

Are filler necks supposed to fit inside the hole in the tank fitting? Are they to be the same diameter as the tank fitting? Am I missing parts with this tank?

This is all new to me, and the engineer in me says that there should be a thin wall tube that connects a filler hose to the tank, ensuring a leak-free fitting with the hose. The ID of thee hole in the tank is about 1.5".







Tank fill fitting sits on the side of the tank at about a 45 degree angle up in the rear left corner of the tank. I'm thinking flush mount cap, but I need to know what parts I should be looking for.

Thoughts?