I have a 92 WR III and am quite new to these things. I live on a river that has "brackish" water from the ocean. I leave the WR in the water but would like to flush it out after the weekend but not convenient to take it to a water source. I do have a tank I could fill and let run gravity to the engine. Would that work? Also what is the best fitting to hook to? The one on top of the engine or the one with the screw plug in it?