gas trimmer stop button not working

[cadman33619]

I have a ryobi S430 gas trimmer.... the stop button is not shutting off the engine. i replaced the stop button easy enough but that did not solve the issue. it still will not turn off using the button. is there some other issue that could be causing it not to shut off?

the unit runs and works great, otherwise

thanks

 

[reynoldston]

The off button is a very simple device. It has two wires to it. One wire go's to the engine chassis as a ground and the other go's to the coil primary side. All this dose is ground out the coil to turn the engine off when the switch makes contact to the ground.