The rule of "last thing messed with caused the problem" suggests that your primary filter did not seal properly and is letting air in. What kind of primary filter is it? If there's an O ring or gasket involved in the part you opened up, I'd replace that.
2000 Beneteau 331
Northern Chesapeake Bay
Ambition is a poor excuse for not having enough sense to be lazy ~ Steven Wright
Last edited by arf145; 11-09-2011 at 10:01 AM.