Boat gas tank question

[Latenight Bite]

I have a 1979 55hp Evenrude motor. I replaced the gas tank and have been having intermittent issues when I go below ½ take of gas. It runs rough, stalls out at high speed, and acts like it is not getting the gas it needs. I had the boat in last year for a tune-up and the carb cleaned. Again it worked well till I hit a ½ tank of gas. The old take was a metal tank with a pickup tube. The tank I replaced it with is a new style plastic tank without a pickup tube. Could the new tank be causing these issues? Do I need a take that has a pickup tube for the older motor?

[FM_Mike]

I may be wrong but I believe the plastic tanks Have a pick-up line. I know my old tank did. If there is a pick-up line that sounds like where to begin. I had a Plastic tank were the pick-up line had gotten eroded for lack of a better word and did the same as you are talking about. Line could be rotted or just not going to the bottom of the tank.

On my old tank, take off the connection where the gas line comes off the tank. You should then be able to see if the pick-up line is eroded,kinked or has a hole in it. Thats where I would start.

Mike

[suncruiser234]

More than likely it is your hose or where the fitting connect. Are you opening the vent on your tank? It sounds like you might be getting air in the line. I had this problem with my 9.9 and a new fuel line cured it.

[hydro]

Chech the O-rings in the hose, both ends. If they get damaged, they leak air into the line and can cause the problem you describe. They are easy to replace, just push the check ball back and R&R the O-ring. You can get them at your dealer.