What Caused This Engine Damage? - Generac GP5500 Repair

I bought this generator from a local guy (Jason) who buy and sells used power equipment. I was told the engine was previously stuck. He got the engine unstuck and running well. He later sold it to a contractor who promptly returned it a few days later after the engine stopped running. The engine now makes a lot of noise when pulling it over. It still has compression. What went wrong and will it run again? I no longer use Harbor Freight Super Heavy Duty Degreaser in my ultrasonic cleaner. Harbor Freight changed the recipe. The bottle previously stated "NON-CORROSIVE". Now it says "CORROSIVE", "do not user on Aluminum". It now damages most carburetors. Visit My Amazon Store: https://www.amazon.com/shop/jamescondon 3 Jaw Puller: https://amzn.to/47KUibQ 3 Lb Hammer: https://amzn.to/3TfEdXy Amprobe THD Meter: https://amzn.to/46PzSxf Cable Tie/Zip Tue Gun: https://amzn.to/3uVp6YT Dead Blow Hammer: https://amzn.to/46LYEOD EVAPO-RUST: https://amzn.to/3R89w3L Fuel Petcock: https://amzn.to/3ReGTSq Grabber Tool: https://amzn.to/3sWYd6B Kill A Watt: https://amzn.to/3Rv7X1b Micro Drill Bits: https://amzn.to/3Te2NI1 Oscillascope: https://amzn.to/3RwR5as Squeeze Bottle: https://amzn.to/3t7RFBX Ultrasonic Cleaner: https://amzn.to/3uNDqmj If you want to donate to the channel, you can use the YouTube "Super Thanks" feature or via PayPal: https://www.paypal.com/paypalme/jamescondonYT #Generac #GeneratorRepair #SmallEngineRepair #SmallEngine #DIY #Fixed #Troubleshooting #HowTo 389cc, 420cc, Alternator, Backfiring, Bad Oil, Bonded Neutral, Camshaft, Carburetor Clean, Engine Damage, Engine Swap, Exhaust Valve Not Opening, Fixed, Generac, Generator Head Install, Generator, Hertz, Honda Clone, How To, How-To, Load Test, Repair, Rust in Fuel Tank, Rust, Small Engine, Troubleshooting, Ultrasonic Cleaner, Varnish, Will Not Start, Wire Insulation, Won't Run, Worn Camshaft, Worn Lobes