I am having trouble getting my lawn mower to start. I have run it a
few times this year but it seems to have stopped working.

I had the local college kids give it a tune up and I suspsect that
something was not done correctly.

I got the mower back from the college and I found that the blade was
loose. I tighten it, mowed and stored for the week. The next time I
tried to star ( a week later) the engine kicks back and yanks the cord
from my hand.

I noticed that the oil was a little low so I added.

The blade spins freely. The cord is hard to pull and when the engine
seems to want to start it yanks out of my hand. I also get a puff of
grey smoke from the out of the air filter.

Any thoughts?