Hey Folks.
Took my 1986 Formula Mercruiser 350 Mag out of storage and tried to start it yesterday (yep late in the season). Carb was overflowing real bad and totally flooding intake manifold before an observer noticed all the gas.
Upon doing some reading here, of many excellant posts, I almost had myself convinced that a malfunctioning mech fuel pump could overpressurize fuel, made no sense to me, and sure I misunderstood - maybe people putting on fuel pumps with wrong size gasket... anyway I fell back on my old truck carburetor knowledge and went a different route. Once again did some reading here and sure enough a stuck float as I would suspect on a truck.
So all the above to maybe help the next guy and to lead up to a question:
Q. I've read that the extra line off the fuel pump (not on my old trucks) going to the carb is there to vent fuel, to anywhere but the bilge, in case the mechanical fuel pump vents, malfunctions, etc. Can somebody explain how a mech fuel pump failure can cause this to happen?
My experience with failing fuel pumps is on aircraft. When they fail they bypass due to a low pressure/flow - of course this implies other redundant pumps in the fuel sysytem.
Oh and before I forget. I see a few names over and over again helping people like me with questions... you know who you are... just want to thank you!!
Took my 1986 Formula Mercruiser 350 Mag out of storage and tried to start it yesterday (yep late in the season). Carb was overflowing real bad and totally flooding intake manifold before an observer noticed all the gas.
Upon doing some reading here, of many excellant posts, I almost had myself convinced that a malfunctioning mech fuel pump could overpressurize fuel, made no sense to me, and sure I misunderstood - maybe people putting on fuel pumps with wrong size gasket... anyway I fell back on my old truck carburetor knowledge and went a different route. Once again did some reading here and sure enough a stuck float as I would suspect on a truck.
So all the above to maybe help the next guy and to lead up to a question:
Q. I've read that the extra line off the fuel pump (not on my old trucks) going to the carb is there to vent fuel, to anywhere but the bilge, in case the mechanical fuel pump vents, malfunctions, etc. Can somebody explain how a mech fuel pump failure can cause this to happen?
My experience with failing fuel pumps is on aircraft. When they fail they bypass due to a low pressure/flow - of course this implies other redundant pumps in the fuel sysytem.
Oh and before I forget. I see a few names over and over again helping people like me with questions... you know who you are... just want to thank you!!
