Water pump failing to pump water to faucets, toilet. Can't hear pump running when faucets turned on & no water flow. Checked fuses & ok. How difficult is it to install new water pump...(a little mechanically challenged?). Are replacement water pumps relatively standard? Found SHURflo 4008-101-E65 3.0 Revolution water pump. Am wondering if this pump will work in my 2012 Landmark Key Largo. Any thoughts?