If it's a river / lake boat I'd advise a water pump. There will undoubtedly be times when you have no choice but to idle for fairly long periods (marina's etc). It can certainly be done without if it's strictly gonna be running at speed with no idle time to speak of. It also depends on the boat, engine combo, some run hotter than others, just because.A buddy told me I dont need to run a water pump in my Sanger v-drive as long as I dont idle for to long. He says that the water pickups will push water through the engine when I am moving.Sounds kinda iffy to me. Can this work?