[Porsche virgin]

I started my weed-wacker up this weekend for the first time in months (possibly since last year). It runs fine at idle, but when I get to wide open throttle, it dies. What could be the cause? Too rich, too lean? I know very little about fixing these things.

It runs on a gas/oil mix, and I mixed up the fuel in the tank in case the oil settled over time.

Thanks in advance.