This season we needed to replace two pumps. The first was the fuel pump. There was some difficulty in getting it as the person working at the first place we tried was unable to look anything up with out a part number and insisted they were all electric, even though the mechanical fuel pumps are common on older trucks. Thankfully we found educated staff at the local Auto Value and got a Carter mechanical fuel pump replacement (part number M6866), which we installed ourselves. The pump was inexpensive, under $40.00.
The second pump was the water pump, which we discovered was broken, as we were heading out for our first camping trip of 2016. We apparently left it on for months with an empty tank, thus burning it out. The new one auto shut off. We found a SHURflo brand one (part number: 4008-171-E65) at an RV store on our way, planning to install it once we got set up at the campsite. A warning to others, confirm if your current water pump is wired for AC or DC. Our pump was DC and we bought an AC one. With some extra effort, we were able to make it work as we re-routed AC instead of DC. This pump was unfortunately far more expensive than the fuel pump, coming in at $330.00.
So now Myrtle again reliably pumps both fuel and water!