Hey Sam... did you ever figure this out? I am in the same boat. I have to constantly take the plug out and unstop the lines, then I have to prime and bleed to get it cranked... to only get about 10 minutes of run time before it stops up again. Apparently there is a lot of gook in the bottom of my tank that needs flushing... and a new screen/filter installed. Most aggravating to say the least.