On December 8, 2019, about 1515 central standard time, an experimental, amateur-built Zenith Zodiac CH-650, N914AR, was substantially damaged when it was involved in an accident at Willow Springs, Missouri. The private pilot sustained minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. According to the pilot, he adjusted the ground adjustable propeller and was going to test fly the airplane. During the initial climb, the engine lost total power. A few seconds later, the engine restarted on its own, but shortly lost total power again. He turned back to the runway but knew he would not make it and set up for an off-field landing. The pilot did not recall additional events leading up to the accident. Examination of the airplane by a Certified Airframe and Powerplant mechanic revealed that the fuel pump was weak on pressure and the diaphragm was leaking. The electric fuel pump was installed between the engine driven pump and the carburetor, causing low fuel pressure. The fuel flow meter was not installed correctly using the proper fittings. The fuel flow meter was installed using a pipe fitting connected to a flare fitting. All fittings were finger tight.