Mowed lawn then when finished, mower won't start up.

[outdoorman]

I have a Ariens riding mower with Briggs Stratton 17.5 that was running well but after finished lawn, it won't crank up/restart. What can be wrong??
It started up fine initially, but after I finished lawn then wanted to restart and all it does is slowly crank and only partly turn the flywheel under the hood...maybe 1/2 turn at most before just stopping.
I cleaned the cables (which weren't dirty), fully charged the battery overnight and same problem not starting today.
What can be the problem???
I don't know much about small engines but I know it's not the carburetor so assume it's in the starting system...solenoid, starter??? How can I test these.
The mower is too heavy to push up back onto my trailer so is there a way to jump start it??

 

[bertsmobile1]

Take the spark plug out and try to turn the ngineover by hand NOT THE STARTER.
If no petrol gushes out of the spark plug hole then secure the spark plug out of the way & try with the key
Let us know what happens .