Never heard of that one. Could be inviting danger but more than that isn't it easier to just pull the mower through a few strokes to clear it out instead of going for the plug wrench?

I'd put the Bic on a plug in a heartbeat, but not on the plug hole. Just once with a little spilled fuel or the cap not on tight would be a lesson I don't want to learn.

It doesn't take much of a "poof" to end up without eyebrows.

Your description of the mower starting after filling the tank and then going dead shortly later doesn't indicate a flooded condition. Anyway I tend to come in on the conservative side of this one and cast my vote against your lighter procedure as being on the dangerous end of the spectrum. A truly flooded engine would not be un-flooded by that procedure anyway. A few pulls at wide open throttle would get a mildly flooded engine going most of the time.

I have noticed similar effects from a CD pack which was getting too weak to fire dependably or a spark plug that was dirty or old. A cheap fix could be simply trying a new plug or installing one every year as recommended. No, I would never apply an open flame to a mower in that way, particularly just after fueling. Like they say, better safe than sorry in this instance.

Gentlemen, allow me to make a few comments in my defense.
First of all, there is little chance of me singeing
my eyebrows because I don't put my face anywhere near
the plug area, as there is sometimes a very violent
'pop'. In this case I didn't beleive the mower was
flooded either, but pulling the plug confirmed I was
right. When I do this 'trick' it is never in or near
any buildings and I always plan an escape route
just in case, but then I do that whenever I'm performing
ANY repair, because you never know when something unexpected will happen. And lastly, I make sure there
is no raw gas on or near the mower and always sniff
for fumes. Sure I could have left the plug out and
come back in an hour and accoplished the same thing,
but rain was quickly approaching and I only had a little
mulching left to go. I have found this method is a really quick and easy way to get back to the task at hand and have
been using it for almost 50 years with great success.
Having said all of that, I would like to end with a
thanks to you all for making very legitimate comments
since I respect your opinions, or I wouldn't be on
this forum in the first place.

I have to admit I have done similar things myself. I may even try your lighter trick...who knows. Many years ago the only way my brothers and I could start a Westbend 2 cycle go-kart engine was to unscrew the plug and put a good squirt of Ronson Lighter Fluid in the hole, replace the plug, and pull the starter. It usually resulted in an 8 inch flame thrower out the exhaust pipe just before it started. So...lbpod, I'll give your method a try next time.

An escape route is pretty much irrelevant given the instantaneous nature of most explosions. Raw gas won't be the cause, but fumes from gasoline or something else could be. It is not something I would try and I've been working on motors for close to the half century mark too.