I've had one of the original, and a replacement valve fail. Thankfully I pay attention to the fuel gauge. And noticed that after switching over to the AUX tank.. The gauge wasn't dropping. So I pulled into a rest area. And switched the hoses between the tanks. I never run the tanks below 1/3 for that reason. Running till the low fuel light comes on to me. Just isn't a good idea for this reason. This two pump setup is simple. Should have done it with the carb setup. Bob Dunahugh