I got a 1983 25 hp Johnson recently, it ran well at low speed with a flusher attatched to it without any problems for a few minutes. I brought it home and tried to run it in a tank but now it dies soon after starting and after starting it right back up it seems to run for a shorter period of time. After starting it up a few more times it finally will not start anymore. I had primed the gas line until the ball had pressure. I noticed the fuel lines were clamped on with zip ties and there might be a slight leak in the hose going out of the fuel filter. Is it possible that air is getting in the line and this is causing the motor to die? The plugs seem a little wet but not black and grimey.