sorry, but you bough the only pump I know of that says, "not made for continuous duty". That means it is a very lightweight pump, made to not last very long, even with very light duty. Yo are trying to irrigate with a pump made to barely fill a dog water bowl.
To irrigate you will need a pump made for continuous duty, and a pump control system that will keep it working continuously while you are irrigating. With a normal pump it is the cycling on and off that wears them out. That pump is must cycle while using water, just not cycle very often or run for very long.