I found even 18 gauge runs the pump fine with a distance of 12 feet.
I have 2 pumps, both marine, one is carter the other Holley red.
The wire is cable from a vacuum cleaner, has heavy fiber strands in the cord to resist breakage and is tough. One wire is 18 gauge, the other 17 gauge. I too wondered about the gauge but It pumps fine.
The flow is like this,
anti siphon valve at tank fitting
pump mounted behind engine on a wood support
Putting filter before pump works. the filter top is at same height as tank top, the pump about 5 inches lower than filter top. The filter acts like a small tank right next to the pump so it flows. I do fill the filter housing with fuel
first after a change but dont know if need to do that.
USCG has a rule
that pump should be mounted within a foot of engine, mine is about a foot behind the engine. I have seen pumps on other boats mounted all over bulkheads even far from motor
. So dont understand that rule
except perhaps have it close to engine for monitoring function?