My Insinkerator 777 hums when turned on but won't spin... unless I stick a big spoon down and give one of the spinners a good shove, like starting a prop plane. (Pretty easy for me to do since my baffle is in bad shape and I can easily see my shredder assembly.) Obviously, then, my flywheel isn't frozen and there's no food stuck and the reset button hasn't switched off, etc. It works as good as new, except for that pesky little problem of not starting. :-) I've read countless GD questions here and elsewhere and the answers seem to be either one of the aforementioned issues or "time to buy a new one," but I've not run across my situation of it running great after a "push start." I'm not sure when we got it -- could be ten years old -- but, regardless, I hate to trash a $350 GD that seems repairable. My only thought is perhaps the capacitor is shot. Does that sound plausible? Worth buying one and trying to replace? Has anyone encountered this problem before and is there anything I can do? Thanks for any suggestions.

The Insinkerator 777s does use a start capacitor and the symptoms you describe indicate that it is defective.
https://www.plumbingsupply.com/insinkeratorparts777ss.html
Part #38

If you have some electrical skills it may be worth $15 to try to replace the capacitor.

From my experience, buzzing sound may also mean something is preventing grinding wheel to start spinning. Usually, it is a small piece of bone, fruit seed, or piece of nut shell, lodged between body of the GD and the grinding wheel. This is usually fixed by putting stick inside the mouth of GD, and helping the grinding wheel to start spinning.

The ISE 777 is quite an expensive unit. I would make sure it is not something simple before I go out and spend money on either new one or replacement parts.

Try this: UNPLUG Garbage Disposer from power supply. Remove rubber splash guard (rubber piece inserted inside mouth of the GD inlet). Take flash light and look inside. You will see a grinding wheel with 3 blades and the interior shell of the GD's body. It has lots of small holes in it. Follow the grinding wheel with your eyes around its perimeter. Take wooden broom stick, stick it inside, push it against the grinding wheel and try to slowly spin it. See if you feel any kind of resistance, grinding, or repeating clicking sound. Wheel should spin freely and quietly.

Let me know how you did

Milo

In the first post the owner indicares the disposal does run after he gives the grinder wheel a spin. This would inicate that it is not debris. Motors have a second winding that I call starting winding. It takes more power to get a motor to spin from a dead stop, once it is running this starting widing drops off. This could also be bad. If it is the motor I would not try to repair.