Originally Posted by
goose
Steve, you are right. The truth is specifications are not all the same. You can look some places and it says 9 gal/min, some say 88lbs/min but they usually aren't really clear at what voltage they are measuring that at. Some say 12 volts, but some companies take 12.0 as 12 volts and some say 12.5 or 12.8 as 12 volts. It really does make a huge difference at what true voltage the pump is running at. And it is not linear. Try filling the pumps sometime with the key off, then turn key on and rev the engine. You will hear a huge difference in the sound of the pump. At 13 volts and higher, that pump really cranks some water. In addition, as some have said, there is WAY more hose and pressure in the front and filling a bag by venting the tank does take longer. So, you are correct, it probably should take about 13.5 minutes to fill the 1200lbs most of the time. You probably don't have a problem with the impellors if you are taking slightly longer filling it with key off.
And I think we can probably add another minute and a half or 2 minutes to the timers. Just don't tell my boss.... hahaha