Hello!
You sure don't need a pump! A pump is only needed when you have the tank positioned on the C of G.
Pictures show that you have the tank too low!!!
And for best results you better use either a Tettra "bubbleless tank from Dave Shadel, US Y&S importer or...the tank you have... set up in a "Uniflow" way with two clunks.
The picture you have shown is correct but the vent line must be attached to the pressure nipple once you are about to fly.
You would be much better off if you mounted your engine side-ways instead of right up the way you have now, that way the center of the tank could be positioned correctly at the center of the carb intake.when the airplane sits horizontal...which is very important.

Regards!
Jan K
Sweden