Fuel pump mechanism question
So I decided to re-mount my fuel pump and wanted to check whether it was working.
I took it apart and to me it definitely looks it also has a vacuum plunger that closes off the fuel flow when the engine stops running.
However, my pump is flowing crazy amounts of fuel with the engine off.
To add to my confusion, there's no vacuum line to open up the diaphragm. Is it operated by the same vacuum as the actual pump?
How?
I opened it up put my finger on the blue circle (where the plunger normally sits):
I pressed my thumb into it hard (which should close it perfectly) but when I put the tank on PRI, fuel is rushing like crazy because of 20L of fuel pressing on top of it.
How in the world is that rubber plunger cap supposed to stop it?
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