All Stihl products use a 50:1 mixture
The fuel mixture for a Stihl chain saw is gas and oil.
50:1 Stihl HP Ultra oil
50/1
50-1 on 2cycle engines
50:1
50:1
50-1
If you accidentally put regular gasoline in your oil-gas weedeater, do not start the engine. First, remove the fuel tank cap and drain the contaminated fuel completely. After draining, you should flush the tank with the correct fuel mixture of gasoline and oil to ensure all residue is removed. Finally, refill the tank with the proper oil-gas mixture and check for any issues before starting the engine.
Look on the Gas cap of your weedeater. It should tell you the gas to oil ratio. If its not there try looking in the manual or online.
I purchased my Toro weedeater in 2007. It uses a 50:1 gas/oil ratio.
50 to 1, using a quality full synthetic oil like Stihl Ultra. Don't skimp on oil. Use the best.
If you use Stihl genuine two stroke mix, then the ratio is 50:1 eg 500ml to 25 litres fuel