I have recently replaced my main two stroke engine and two stroke kicker with one four stroke engine. I used to run two tanks for the main, going through one water separator/filter located on the starboard side of the transom, and one tank for the kicker through another water separator/filter, mounted on the port side, both 10 micron. I am now going to run all three tanks for the one engine. The two tanks on the starboard side will go through both the filters before going to the engine, while the port side tank will only go through the filter on the port side before going to the engine. After all that preamble this is my concern. At this time I have not installed any shut off valves. Will the engine draw from both the port and starboard tanks if i don't install separate shut off valves? My instinct says they will, however if the fuel follows the line of least resistance then perhaps the engine will only draw from the port side tank as it only goes through one filter. If anyone else has done this, if so what did you find? Even if you have not done this, what can you speculate will happen.