Question on dual fuel tanks on a 41
 

Hey guys. Tried searching for this but didn't find anything, at least on the surface.
Can one of you tell me how the dual fuel tank setup works on a 41? I have twin ball valves at the helm for Main or Front tank selection. When I turn the valves, does the fuel just drain/pull back into the main tank or do the engines actually run directly from the front tank? Do the valves simply change the fuel pull from one tank to the other? I haven't had a chance to spend time chasing lines and figuring this all out yet. I'm sure a few of you guys know though.
And I assume if I wanted to drain the front tank, turning the valves won't create a gravity feed?
In addition to just having the knowledge of how the system wiorks, I'd also like to drain the fuel out of the front tank and start with fresh fuel, just trying to figure out the best way to do it, rather than having to pump it out.

Thanks!
Rick

in my case tanks all go to the directional dash valve from there to the eletc. fuel pump-- fuel filter and to the eng. mech block pump and at that point copious amounts of money are blown out the tail pipes (and worth every cent)
if you want to gravity drain them put a hose on the filter in side before the filter run the hose out the bilge drain hole into a can and blow on the vent to get the siphon going