To my knowledge, all of the farm fuel trailers come with gasoline engine driven centrifugal pumps. Most are the 5 hp type Honda or clones. Much-much faster than electric. You can run them at an idle, or vary the throttle to your liking.

I'm guessing they will last forever vs electric, especially if you spend a few minutes "winterizing" the engine and change oil occasionally. 

If your trailer were mine, I'd switch to gas-driven pump.