Jabsco Bilge pump on 373

[JDW]

I have a Jabsco Par Jabsco Shower/Bilge pump that was not drawing water out of the bilge. Seemed like it was trying but weak. I rebuilt the pump with the major rebuild kit and now it (back pressures?) blowing bubbles into the bilge. Any ideas on the issue may be?

 

[Don S/V ILLusion]

Among the guesses - bad pump, bad check valve if one exists, weak pump, low voltage to pump, obstruction in line, air leak ….
Just a suggestion for future reference - generic questions would be better posted in ‘ask all sailors’ rather than limited to just one builder sub forum to reach the desired target audience.