The risks of running an AEG without a fuse?

What are the risks of running an aeg where the battery is hooked strait up to the motor?

The reason why I ask is because i have an AEG here that began its life as a CA Sportsline(Not great but not the worst). To further the abysmal state of the gun its a few months old and had seen a bit more then average abuse .
And to to make it even worse it came from Munster Airsoft!:eek:

Now at first it worked and then all of a sudden....... nothing the stock 13a fuse had went so i replaced it and boom it went strait off not a budge out of the motor so I figured maybe theres something internally maybe the gears are misaligned or they weren't properly shimed or greased but still to be sure to be sure I had the thing gutted and rebuilt and apparently all is well

Not the case as it now has a 20a fuse and that went the second I plugged in and 8.4v battery but figured it could have been a used one that was lying around and was just on its last tether but i replaced it with a brand new one and that went aswell at the drop of a hat :pac:

So now my only conlusion is scrap it for parts or feck the fuse?
What am I risking by not having a fuse?