My Ryobi start great but when I change it from start to run stays few seconds and died

this sounds strangely like the high speed jet/pathway in the carb is clogged up with something ,

the best way to fix it is dissasmbly and cleaning of carb in solvent , but ive also had some limited sucess in past of using car fuel cleaner (says on bottle "cleans as you drive") too

I would need more information to give you a good answer. I need to know how long will it stay running a few seconds an hour what is it. I had a 2000 blazer that would start fine everyday and i would 10 minutes and it died sometimes i drove an hour and it died. I parked it and everytime i started it would run about 10-15 minutes and die. after it would die i would check fuel pressure which was good and spark. Well turns out there's no spark so i changed coil ,plugs, wires, rotor. I finally changed the crankshaft positioning sensor and that tuned out to be the problem so good luck.

Fuel pump and filter are suspected, consider replacement.

Check the fuel filter or better yet, go ahead and change the filter. This should resolve your problem.

replace the carb. You are flooding the engine because there is an internal leak that a carb kit won't fix allowing the gas to continue to flow

If you need further help, I’m available over the phone at https://www.6ya.com/expert/kelly_69a0cf1b13789df1

sounds like ethanol problems,clean the plug and use a carb or injector cleaner.If that wont do it check the plug wire to make sure it has a good connection.

Yes. You just need to do a simple carburetor cleaning. Disassemble the carb. and spray with carb. cleaner. Make sure the small screen is in carb. is free of debris. Use a Den Tek Brush,(http://www.dentek.com/shop.php?target=products&product_id=7), to clean the small portals in the carb.
If you need further assistance, just let me know.

Jim

can be your plue

Check the crankshaft position sensor. If the plug is loose or the sensor itself is bad it will cause similar problems

Does the engine die as soon as you release the key, or does it run for a couple of seconds after you release the key and then die? If it dies as soon as you release the key, try holding the key for a few seconds and see if it will stay running as long as you are holding the key (the starter will make a grinding sound while holding the key but won't hurt anything). If it stays running while you hold the key then dies when you release it, that indicates that the ignition switch is bad.