I am still undecided about the fuel pump after struggling with it for a year. It is the Facet that has been recommended by several people.
When first installed, I noted that it would nearly flood the engine and that an immediate leaning of the mixture was required whenever it was turned on. I solved this one by installing a 5/32" bypass line from the pump outlet back to the header tank. Mixture adjustments from pump on to pump off are now minimal. With the pump off, I can cause the engine to stall at higher RPM by setting full rich and waiting. It seems the free-flow (gravity only) rate through the pump is just barely adequate and eventually the gascolator empties and the engine stalls. I can always remedy this by turning the pump on for a couple of seconds, so I am convinced it is a fuel starvation situation. I installed a "T" before and after the pump, and made another bypass, 5/16" diameter with a one-way valve. With the pump off, the theory is that fuel will flow from the header tank through the one-way valve and out to the engine. This effectively creates two flow paths from the tank to the engine. Even with this, I heard the engine stutter a little after about 15 minutes with no pump. Again, just bumping the pump for a couple of seconds cleared the situation. I am very close to reverting to gravity only feed, and am interested in who runs gravity only, and what, if any, obstacles they had to overcome. My main concern has been vapor lock, and the pump is very effective at clearing situations like this. However, getting adequate fuel flow when the pump isn't running has developed into a real challenge. If I keep the pump, my preference is that it NOT be used for normal operations. What have you that use gravity only encountered in your low fuel situations, climbs, etc.? The entire fuel system has been cleaned and cleaned again, new filters, everything. So it appears that I'm fighting purely a flow situation when the pump isn't running, and not some unknown restriction or blockage. Any thoughts or comments would be appreciated. Thanks, Dave.
