77 440 Motor Home

I didn't know this but it makes sense. If the fuel tank is 20 feet from the engine, you'd want more than the basic mechanical pump to do the job.
spent half a day trying to get it fired off, finally seen machinical pump and primed it fired up run good. undid electric pump and then tried to move it got weaker and weaker till it died! figured pump died, towed it! then found out thay both work together, i was thanking the electric was for generator! made me feel dumb but hay, good RV for 320 bucks after tow, got rest my life to learn the RV world!