I was riding my 300ex turned it off tried to restart no power

It sounds like you need to adjust the shift lever or move it in an out of gear while holding the starter switch on. this will tell you it's the lever not the switch.

blocked main jet in carby
no/low fuel flow to carby

Losing all or most of the engine oil is potentially disastrous and you shouldn't be trying to start it until someone with experience has looked it over and declared it fit to attempt to start it and then proceed cautiously, checking and diagnosing as it progresses.

You might be very lucky or the engine might need dismantling...

sounds like, a valve clearance adjustment problem. starts when cold, looses some power when hot, if turned off or stops, won't restart until cold.

Most riding mowers do not cut in reverse. If PTO is on and you put in reverses a safety switch will turn PTO off.

I’m happy to assist further over the phone at https://www.6ya.com/expert/layne_0fccff498c319c32

CHECK THE BOOT THAT GOES OVER THE SPARK PLUG IT MIGHT NOT BE TOUCHING THE WIRE.. ALWAYS TRY A NEW SPARK PLUG

pull the top cover and see if the starter gear broke if so napa has them for about $10

you are having problem with the connector i;e power button try at some good repairing shop

Hello mdonettaYou said,
Dryer shut off towels were not yet dry, turned dial to restart dryer acts as if it isn't getting power I closed door and pushed start button. Nothing! Checked breakers and power cord at outlet all checked okay. Any ideas.

yes, try unplugging the power cord or turning off the breaker for 5 minutes. Either will due. Some times the system needs to be reset!
If this does not work there are internal fuses that can be replaced!

Let me know how it goes!
Huuum