I ran a fuel system test on my 1976 searay with a 5.0 on a 233 outdrive. Vacumn was tested between the fuel filter and the tank. running on muffs (i know) it was -5. If I pinched off the gas line between the test gauge and the tank the vacumn pressure rose to -9 psi. At the same time a pressure gauge was in line between the fuel pump and the carburetor, it was 5 psi. I ran engine until normal operating temp (on and off at 1000 and 1500 rpm). Pressure and vacumn remained constant. I turned off motor and the pressure stayed at 5 for 40 min and vacumn remainedat -5 for 10 min. The boat shuts off after 30 minutes at cruising speeds. The tank has been cleaned, the pick up tube was removed and checked and the tank vent has been checked. the fuel line has been replaced and the anti siphon valve was replaced. I will take the boat out on the lake later in the week to test it on load. Since the pressure remains for so long after I shut the boat off, I dont see how there could be any air leaks in the system.
