So I recently received one of [URL="https://www.amazon.com/XP4850EH-Starting-Electric-Portable-Generator/dp/B00J7V5ENG/ref=sr_1_2?ie=UTF8&qid=1546050033&sr=8-2&keywords=xp4850eh"]these[/URL] as a gift and thought I would change the spark plug to a [URL="https://www.amazon.com/NGK-BPR7ES-SOLID-Standard-Spark/dp/B01DMFHL5Q/ref=sr_1_1?ie=UTF8&qid=1546050097&sr=8-1&keywords=ngk+bpr7es"]NGK BPR7ES[/URL] Problem is, the generator started just fine with that plug two days ago, but today it would not no matter how many times I pulled the cord or pressed the button. Couldn't get anything from the engine at all. I thought maybe the engine just died outta nowhere. I put the original [URL="https://www.amazon.com/Stens-131-055-Spark-Torch-F7RTC/dp/B005LA6490/ref=sr_1_1?ie=UTF8&qid=1546050217&sr=8-1&keywords=F7RTC"]F7RTC[/URL] back in today and finally got the thing to start. It's still running right now. What is the problem? NGK are suppose to be good plugs. Why would it start the first day, but not the next? Also, the manual calls for F6RTC/BPR6ES. Why is an F7 in the engine?

Honda self-propelled lawnmower powered by Honda GCV-150 engine. Engine is a Honda 160cc 4-stroke vertical shaft rated at 4.4HP @ 3,600 rpm. I was mowing the front yard when suddenly it belched a big cloud of smoke (from the smell musta been motor oil) and quit. When I looked at the mower, there was oil around the muffler outlet and spattered on the right side of the mower body. I tried to start it but no dice. It also seemed VERY easy to pull the start rope. The engine is easy to start but there is almost no resistance. The mower is approx. 3 years old. Other than not liking old gas it hasn't given me a minute's trouble. It doesn't feel like it's got any compression. But I have NO expertise with small engines so I'm outta my depth here. Most likely I'll take it to a repair place but I wanted the thoughts of the folks here upon what failed so I'm at least somewhat knowledgeable about the real problem. I'm old and some people like to take advantage of seniors. I'd fix the thing myself but I don't think I have the tools to break an engine down; plus my arms aren't as strong nor my hands as steady as they once were. Gettin old ain't for the faint of heart. Thanks in advance for any help you folks can give an old man. :help: