Here's a quick and easy potential solution to a blocked pickup. I just removed the primer bulb and reversed it, so when I squeezed it fuel was pumped back to the tank. A little gentle pumping and I had a free flow back to the tank. I put a fuel conditioner in the tank, so I am hoping that with the sloshing around in the tank, the sludge will slowly dissolve and get burned or caught in the fuel filter. I reversed the bulb again, reconnected the lines and ran it. It does not suck the primer bulb flat as it used to. I am declaring victory.