Valve adjustment issue on my mower?

[SAWYER]

I have a Craftsman riding mower that I have been boosting to start and the last couple times I trued the engine will only halfway turn over then stop and this repeats each time I try. I took the spark plug out and it turns over freely. According to a google search a lot of people seem to say adjusting the valves might fix this issue, what does at garage think?

 

[franksta]

It's worth a try and doesn't cost you any money. I'd give it a go.