Probably your only option.

Black oil? Probably flooding it and the gas mix turning to carbon due to the heat of the exhaust. I would take the muffler off clean all the carbon out of it. let it.

It's not just the cheap weed trimmers two strokes that do it. My Sthil Blower does the same thing and will clog the muffler screen and the blower won't start if I don't burn the carbon (black oil that makes it out of the muffler, yes I use the expense sthil two stroke oil at 50-1 mix) off every season. So I would imagine all two strokes have this problem which most ignore until they won't start or run at WOT.

Thanks, do you have a good method to remove the carbon from the muffler?

Propane torch and wire brush.

I have been thinking about the black oil on my weedeaters.I believe that it is caused by how they are used, I use the weedeaters to edge the lawn usually at low speeds. I believe that I am not getting the mufler hot enough to burn off the oil. My other 2 cycles are normally used at a much higher speed. I guess that I need to either run the weedeater at a higher speed or just wipe the oil off.
Thanks

I wouldn't worry about it. You run it at higher speed you will be using lots of string at the cost of occasionally cleaning muffler or spark plug ever other year which you may have to do anyway?

Wat if is to much oil mix ratio with the gas???

50:1 is not too much !

I got 6 different types of brush cutters and only the Ryobi is leaking black oil since new

black oil is 2stroke oil not burned. So either there is too much in the mix, (50:1 is not too much) or its not burning efficiently (check spark plug etc) or the carb needs to be tuned to lean the mix a bit. But remember too much oil is never as bas as not enough.

This is 10 years of carbon buildup on a echo 225 the jugg is just as bad I'm having problems with it blowing out oil out of the exhaust could this be the problem.