Install a new plug , if it's wet looking it's not firing - there's your power loss, The type of gas you used does not effect the rings / compression etc. It's just a lower octane and does not deliver the needed power for your machine.
I suffered through a tank of this by keeping the machine choked but do not fool with it anymore,
Pull both plugs and ground them while cranking over the machine , they should both show a spark if one does not, it's bad or the coil wire attached is not. Swap the plugs over and retry to prove it's the plug or wire attached.