manual spark advance / lawn mower

[broker-len]

I was mowing the lawn with a gas mower     shut it down for just a few seconds   as I prepared to put the cord I noticed there was already a charge of fuel in cylinder ------a little stiffer   pulled it anyway and it backfired before ---TDC---pulled a mussel in my arm       now I will use the electric mower for a while

[Dandy Dave]

You have to pull her though hard and fast. You can't pussy foot around. Most of the time when they kick on me I end up with a broken rope.  Sometimes if you hit something hard with the mower blade and stall it, it will shear the aluminum key enough to change the spark. Dandy Dave!  

[Rusty_OToole]

Sounds like your spark is too far advanced. It should start easily and not backfire if everything is right.

[broker-len]

With an empty chamber there is no problem     I think the issue was standing fuel in motor and my right arm not as strong as it ones was

[TexasJohn55]

That is normal with mine also after short hot shutdown.  Re timing:  The blade acts as a flywheel, acting to continue rotation by the mass inertia.  Try removing the blade and cranking up the mower, violent kickback. I learned this as a kid fooling around with old mower engines, only found one that would consistently crank up without kickback when blade was removed. I learned if I pulled it FAST I could crank it up. Also had very aggressive throttle response,  kinda like my Buick 264 without the torque converter bolted up.😉