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Elite Veteran
 
Location: Medford, OR | I found an existing mount (no pump), and 12v +&- wire...but not sure yet where power comes from to power the old electric pump yet...
Is everyone/anyone running electric fuel pumps inline with there mechanical pump carburated 440's?? Or do you remove the mechanical all together?? Or, has vapor lock not been an issue? I'm getting closer to driving 850.
I have to run an electric pump on our 86' P30 to prevent vapor lock now...but our P30 has a fuel return line built into the mechanical pump, so I'm not afraid of blowing out the diaphragm.
Dan
#850 |
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Expert
Location: Cottage Grove, OR | Dan, whenever I have run an electric pump I have always bypassed the mechanical pump due the risk of pump fuel into the crankcase as you have described. When I still had the 440, I ran the mechanical pump until I switched the fuel injection system and then the mechanical pump was removed, a plate put over the opening in the block, and an electrical pump installed.
My personal opinion is that one should run one system or the other and not mix them. It keeps the trouble shooting simpler. Either pump is small so a spare can always be carried if one feels the need to cover the possible loss of a fuel pump. |
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Veteran
Location: Soquel, CA. | I recently added an aluminum manifold along with the new carb. So, theoretically, I increased the chances of vapor lock. So, we added a second filter that has one in and two out. The second out is for vapor and is routed back to the gas tank. This supposedly reduces chances of a vapor lock. I can say that on my recent 6000+ miles trip, no vapor lock. I just can't say if it would have happened or not without the special filter. Still use the mechanical pump, by the way. |
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Elite Veteran
Location: Medford, OR | Did you tie the second out port from the filter to the vent port line on the fuel tank? My vent line from the fuel tank just hangs around in engine compartment, smells of fuel, still haven't delt with that yet.
Can you post a link on what filter/housing your using? |
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Veteran
Location: Soquel, CA. | I cheated. I had taken out my generator, so I had that line lying around. I used that one. My vent line is still there. |
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Contributor
Location: Salem, Or | Just a couple of comments; 1---An orifice should be used in the vapor return line to limit liquid fuel return to the tank. Air and gaseous fuel can pass easily and quickly but the pump volume (output) limits are less likely to be exceeded at full power. 2---Parallel fuel pumps should be arranged with check valves so that priority is established beyond both pumps. 3---The electric pump can be wired with a momentary contact switch for filling the float bowl prior to engine start and a parallel switched source for continuous operation in case of mechanical pump failure. 4---The momentary switch can be located adjacent to a fuel pressure gauge so that the filling of the float bowl can be observed as well as pump function on the road. 5--- An electric pump wired for any form of continuous operation should use an automatically actuated shutoff switch to stop fuel flow in case of engine stoppage (such as an accident). 6---A pressure regulator should be incorporated close to the carburetor so that manufacturers input pressure limits are not exceeded.
All IMHO. |
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Electric fuel pump
