Go into the box at 160 with water pump on and at the trailer at 175. Get me some pics of the suction side of the pump to the cell,when your getting the others. There is a reason it wants all the fuel and its not because it makes power to use it all. Additional fuel may cause more issues internally, this stuffs simple and your combo isn't unlike 100s of other's just like it that require less fuel and run faster. A fuel restriction or sucking air on the suction could cause it to want more then needed.
Your nozzels, do you have brass filters or foam style? And do you have the o-ring on bottom or top of filter?