I have owned a 1990 Tristar, I know want you're talking about. For others information, the gas tank is located in front of engine, were some ski lockers are located. The hose should turn-up, above the vent port (gunwall) as high as possible, before going to gas tank.
Another tip, requires re-installation of the vent. Rotate the vent, slightly towards the stern.
Then do the loop, like above. (This won't help, if you submarine, yout boat.
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