[Cam]

You need to try to run a new hose from the plastic tank straight to the bulb. Just run a cut end of the hose directly into the plastic tank into the gas. If the bulb still collapses, it has to be the checkvalve on the intake of the bulb. I would bet money that the fuel hose has delaminated inside the hose. Fuel hoses are a hose within a hose. The inner one collapses after continued use of ethanol gas.