Hi, maybe someone can steer me in the right direction here. I have a 88 Skeeter with the Mercury 175 outboard. The problem is this, I can fill the tank with fuel and it runs fine. Once I get down to about 6 gallons left in the tank it dies. The pump ball will not pump up (sounds like it's sucking air) and of course it won't start untill I put more fuel in it. Shouldn't it continue to run until the last 6 or 7 gallons are used? Thanks with any suggestions on where I should start looking.