Fuel draw issue

[Marq]

So this might be on the forum somewhere but I did not see it.
So my port engine has been having issues where it does not want to startup easy and then will idle for about 5 then die. Out of gas and the in line filter looks empty. When I get it running it will run good. But if I drop to idle for to long it will die.
So today as an experiment I swapped the fuel lines around and now the starboard is not starting and the filter is empty. I ran air into the line back to the tank and it bubbled with no issue and seems to be flowing easy.
So I am having a fuel draw issue. My plan is to clean out the fuel selector tomorrow but outside of that what else do I do?? What could be wrong?

 

[Marq]

When I swapped the lines around this is what came out into the filter. I’m wondering if I should be sucking out the remaining fuel and try to clean out the tank.

 

[Marq]

Update 1. So I went from the main line out of the tank to the fuel filter to the motor and no luck. I then went from the fuel filter directly into a gallon of gas and it fired right up. So I have no idea. Could it be the extension in the tank? The hose into the tank look clear. I will try swapping it with some extra I have around and report back.
Any advice would be helpful.
Thanks.

 

[Marq]

Update 2. So I think I may have found the issue. The lines on the fuel baffle were wrong I believe. The starboard engine was on the vent line. So I swapped those around and it fired right up. Time for a water test.

 

[Marq]

Update 3. The hoses being wrong seems to have been the issue. The starboard motor hose was hooked up to the vent line and with low gas it could no longer create a vacuum to suck up fuel.
So I think I am finally ready for it to run. Gonna give it a good run tomorrow for a fee hours to really put it through it’s paces.