Wayne: Let me get this straight: It starts, it runs, it will Idle - - but when you increase the RPM it will only run a short time before it starves and stalls. Then after that, you can restart it?
If that's the case... the exact same thing happened to me on my L3901. It was confounding... When I went to drain the water separator THAT'S when it hit me.
I thought that the fuel flow from the tank was not as robust as I would expect it to be. I shot a blast of compressed air backwards through the fuel line that feeds the water separator. Apparently the previous owner allowed LEAVES to fall into the fuel tank. It was an obvious restriction which I cured in this fashion.
Easy to do.