[HoosierDaddy]

My microphor has never worked on the 12V air compressor alone. Today I was trying to sequence the events to determine what to repair. So I turned on 12V comp. and let it run til it shut off. ( probably 7-10 minutes). I flush the toilet and it "stalls out" after the flap in the bowl has closed. It sits there leaking air and gurgling as the 12V comp. runs, eventually the bowl flap appears to leak as the air pressure is lost. Air pressure at the regulator is 5-6#.  If I go to the air pressure regulator and shut the air off to the toilet the compressor eventually tops off the tank and shuts off. Then if I open the air pressure regulator, as the air pressure reaches around 25# I can hear air hissing in the system and then as the pressure builds to 38-39# I hear a small thump in the toilet and everything seals up normally. I have tried this procedure with a starting air pressure of 40# as well as 45#.
I rebuilt the toilet last summer and overall performance improved. It works fine using the engine or 120V air comp. It acts as though there is not enough air volume/pressure to complete a flush even though the 12V compressor kicks on almost immediately.