You will find that the carbureted Pipers have a single fuel line with the electric pump in line with the mechanical pump.
Jeff Scott On Sun, 24 Sep 2006 12:23:47 -0700 (PDT) "Larry H." <lah...@yahoo.com> writes: > Ray, > A lot of certified aircraft, usually low wing aircraft have a > mechanical pump on the engine and an electric pump for start up, > takeoff and landing. The electric pump is turned off during normal > flight (unless the mechanical pump quits of course). There is a > bypass system though. There is a way to hook it up that is dangerous > that some have done in the past and I must be getting old because I > can not remember the wrong way that looks correct. Maybe if I sleep > on it I will remember but I do know one thing and that is that you > do not want only a single fuel line from the mechanical pump going > to the carb and the electric pump only pumping to the mechanical > pump if that is your question. I will take a shot here and say that > you just place a T fitting in the carburetor fuel inlet with the > electric fuel line attached to one of the inlet legs of the T > fitting and the mechanical fuel pump line in the other. As Mark said > there should be a one way valve just on the engine side of the > electric fuel pump to keep the mechanical pump from pumping gas > back through the electric pump. The electric pump may have such a > valve built into it, I can not remember. My old Mooney is set up > this way. On the other hand my old Bonanza has a pressure carburetor > on it, the closest thing to a fuel injection system in the old days. > The pump supplies more fuel to the carb than it uses so there is a > return line back to the left main tank for the excess fuel. That is > why when you fly a Bonanza you always takeoff on the left tank, this > is assuming your left tank is full of fuel when you take off so you > can free up fuel tank space for the returning fuel by burning that > fuel first. If you were to takeoff on the right tank or auxilary > tank for example while the left tank is full, then all returning > fuel to the left main will be pumped overboard through the vent > line. > Someone correct me if the hookup I described is wrong. > > Larry H. > > > > > > > I have an 1835 VW engine, with a Facet fuel pump feeding into a > Bosch mechanical fuel pump. to an EFS-2.. > Will fuel flow through the mech, pump when it (the Bosch) is > not pumping? > > Ray Goree > Ray Goree > 817-795-4779 > _______________________________________ > Search the KRnet Archives at > http://www.maddyhome.com/krsrch/index.jsp > to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net > please see other KRnet info at http://www.krnet.org/info.html > >
