It sounds more likely to be the throttle cable has slipped in its hold down clamp. It certainly will not be due to anything related to the fuel solenoid. The fuel solenoid has no influence that would cause the engine to run at higher than normal RPM.

Engine #s may help. It could also be something as simple as a screw coming out of the throttle plate or something internal as a governor that went to pieces.

the engine no. is 407777 type 0121e3

Do I assume that you mean it is racing? Or won't stay running at low speeds?

IF it sat idle for an extended time, the carb throttle plate may be gummed up in a wide open position.

I had that happen to a small tiller.
With the engine off, the governor opens the throttle plate wide open.

no its been serviced by sears every year this just started half way through the summer one day i started it up and it went full throttle and stays at that speed unless you turn it off

If the engine is actually racing, running beyond what would be wide open throttle- my guess is it would have blown up by now.Correct? Best guess from your description would be to look at the throttle control as mownie suggested and report back with what you find. At least I think you mean that the throttle control does nothing....

My b&s engine is doing the exact same thing only mine started running after replacing the carb. if you get a answer e mail and I will you