Your friend is correct. The valve must be loose so the tank can vent.
I just bought a new plastic 6 gallon gas tank for my Johnson 40HP outboard. I filled it up and took the boat out and it ran great for about an hour. Then the engine started bogging down like it was not getting enough fuel. It died and I had a tough time getting it started. After it sat for a couple of hours it started and ran like a top for about 10 minutes then bogged down again. A friend told me I should have loosened the valve on top of the screw on top on the new tank. He said it ran fine full because there was no air in the tank only gas. Any thoughts?
Your friend is correct. The valve must be loose so the tank can vent.
Fair Winds and Following Seas
Bill H. PTC USN Ret
Chesapeake, Va
Thanks for the info IBNFSHN. You guys are great. If I would have had Cane Pole's handy chart I could have figured out the problem. I am printing that off and putting that in my boat.