Last year I was mowing with my craftsman thst has a B&S 17.5hp single piston....and all of a sudden a cloud of white smoke....but kept running for a few mins then another....I know it's oil...but I just thought head gasket or valve cover gasket....didn't mess with it for a while and the other say I got around to replacing the head gasket... the valve cover gasket looked fine...

So I ran it for bit even made the engine run just alittle faster...all seemed fine when to mow again for about 30min...then bam another cloud of white smoke... slowed it down a bit ans a few mins later another cloud

It was getting late but I also notice part of the muffler that is bolted to the engine seemed to be getting red hot after maybe a min of being on....also if you look at the video it's also dirty in thst area abd looks like the oil is coming out of the valve cover but the gasket looked fine?

So I was reading and they said the red muffler can mean I need a valve job....is a valve job just adjusting the valves? Can the hot muffler or not set right valve making the oil come out the valve cover? (Then hitting the muffler causing the cloud of smoke)

https://imgur.com/a/pUkzmbq