I had a similar problem with a Magnum 91 4 stroke. However my tank was a little higher than the center line of the carb. When the engine was at idle it would load up and quit. I tried adjusting the low end and had no success. What I did was run the fuel line above the height of the tank then came down to the inlet on the carburetor. That solved the low end idle. However when I am fueling up the tank I have to make sure the carburetor is closed or the fuel will leak out of the carburetor.