Toro power max 724 - auger lever wont stay engaged when the drive lever is engaged

Sounds like the safety switch is bad or needs resetting. I had a lawn tractor that did that and I disconnected the safety switch. I know you should not do this but I did not want to put more money into this machine. It does work ok without it.

Belt could be slipping. Could be wet. Pretty easy to tighten cable - follow it from the engagement handle

you need to put in the shear pin dont use a regular bolt

The shear pin is sheared off. Somewhere along the auger, you'll find a hole drilled all the way through it. The shaft inside also has a hole drilled all the way through it. Compare the two augers - the holes are USUALLY in a straight line with each other (when one is up/down, the other is also up/down).

Get a replacement shear pin (DO NOT use a hardened bolt!) and put it through the holes when the auger holes are lined up with the axle holes.

be sure to check pulleys for a rock or anything else lodged in there
then check rear bearing for alot of play up and down

On mine (Honda HS55) it turned out to be gummy old grease on the shaft and the lever that are supposed to lock the auger lever down. The spring couldn't overpower the sticky old grease. If nudged or given enough time, it would slowly turn and lock, but not instantaneously, as it should.
10 mm wrench to remove the nut (bottom left) and bolt (under handle) holding on the metal cover.
Once cover was off I could see the locking lever, spring, and the shaft that had the gummy grease on it.
The third photo shows the locking lever as it should be engaged. I had to push it to engage it, due to the spring not being strong enough for the gummy grease on the shaft.
There are flat sides on the shaft, behind the threads for the nut that has already been removed. Use a wrench on those to turn the shaft out. Disassemble. Clean. Oil. Reassemble. Works great now.
Another possibility is that your locking lever or spring are broken.

bad bearings on the ends , this I would have to see but this is prob it or loose bolts on the auger grab with your hand and see if it is loose anywhere , not running of corse

if shop just repaired it, go back. Right belt? Tensioned enough?

I am not sure of the locking mechanics, or what may be worn and requiring replacement.

I recommend that you contact your nearest authorized service center, or you can download operators and service manuals directly from the Agrifab website by clicking on the provided link:

Downloadable Manuals

I trust this information proves useful.