Surge tank lines

[demuire]

This is probably a fairly daft question, but I thought I'd make sure before fitting everything up anyway.

Surge tank has 4 fittings, 3 up top and 1 down the bottom. Bottom one obviously is feed to engine.

The 3 up top are at different heights, does it matter what goes to what? I would assume the top 2 will be return from engine and fill from tank, and the lowest of the 3 would be surge overflow?

[demuire]

Umm... also, the high pressure pump, does it *have* to be lower than the surge tank? As I understand it is gravity fed, if it is slightly higher than the outlet from the surge (but still lower than the top of the surge obviously) will that be okay?

[HoonBoy]

In order from top to bottom:

Overflow to main tank
Return from engine
In from primer pump
Out to main pump

The main pump can be slightly above the outlet, but the fuel level in the surge tank will have to be higher then the pump for it to work.