Ok guys, first I thought that there was a leak going to my 46FX. There are still some bubbles in the short line to the carb, but I don't think this could be enough to make the engine die like it does.

I've replaced the plug (A3); I thought it ran a little better with the glow starter on, but it still dies with the starter on, as well as off. I've tried different mixture settings, but it definitely isn't a lean/rich issue----not the way it dies suddently after running strong.

It is as if a kill switch has been flipped the way it dies.

Like I said, there seem to be a VERY small amount of bubbles coming from the needle valve (haven't been able to solve that mystery either) but I don't think this can be the cause of the engine suddenly dying.