Not being able to draft is most likely due to what?

Not being able to draft is primarily attributed to an air leak in the system. When drafting from a static water source, the pump must create a vacuum to draw water into the pump. If there is any air leak in the suction line or connections, it compromises the pump's ability to generate the necessary vacuum. This could be due to faulty fittings, cracks in hoses, or improper assembly, which would allow air in while preventing water from being effectively drawn into the pump.

While improper hose connections, insufficient water supply, and a blocked intake strainer could also present challenges in drafting, they are not as direct a cause as an air leak. Improper hose connections could hinder water flow, insufficient water supply would not allow the pump to draw water at all, and a blocked intake strainer would prevent water from entering the pump. However, air leaks specifically affect the pump's capacity to create a vacuum, leading directly to a failure in drafting operations.