This is a replica of a Kelch brand 225 gas cap. commonly used in boating, snowmobiling, and lawn and garden equipment. Mine is for an outboard gas tank.

The middle threads are for adding a vent, if you're tank has one already, I would just remove it in fusion.

It needs a rubber gasket so that the cap isn't constantly exposed to gas vapor and the gas doesn't leak, I don't know how well these filaments hold up to gas/petrol in the long term. I epoxied mine into place and tried to add epoxy to all the surfaces that didn't have any.

Print with the top up, and support the middle threaded section, I left the rest to bridge and it worked ok, filled that part with epoxy anyway. If you print the other way, the threads will not print very well because they are flat-top threads.

I am starting with petg, might need to do PC or Nylon if it doesn't hold up.

Print Settings

Supports:

Yes

Infill:

Notes:

Support middle section of print