Pretty much all my suggestions i have been mentioned . Gotta ask though ,are You "sure" the flow adjust is wide open? How about where the tubing fits to the pump ? Is there any flow coming from there ?
The tubing is too long but shouldn't be enough to back down the pump. It could be shorter however. Could be a wimpy butt pump . I like the suggestion of breaking it down & checking & running it in a bucket to check the velocity of water coming out . Also the bubbles coming out concerns me. Could still be air trapped in the pump . Good Luck !
The tubing is too long but shouldn't be enough to back down the pump. It could be shorter however. Could be a wimpy butt pump . I like the suggestion of breaking it down & checking & running it in a bucket to check the velocity of water coming out . Also the bubbles coming out concerns me. Could still be air trapped in the pump . Good Luck !

