The 250 I have is down right now. Last time it ran was before the 4th of July, tried to start it a week later, wouldn't fire. Pulled the flywheel, cleaned up the points, new sparkplug, nothing. Rebuilt the carb, new fuel line and pulled off the gas tank cover plate and cleaned out the tank. Still wouldn't fire and the carb was leaking gas out the butterfly, asked the old timer at the saw shop, said to check the lever for the needle jet, may have come loose or isn't postioned right, etc. The Super 250 runs great (knock on wood). I'm running it on 32:1 mix just to be safe. Cut 2 loads of cottonwood with it monday and wed. this week and some elm on thurs. The Carlton .404 chain still has a lot of life left in it yet too. And if I could I'd like to find a bigger bar for this one. As for square chain, I knew sharpening it was going to be fun, one of the local shops doesn't even mess with it. The other one said they "might" be able to sharpen it.