Try refreshing the page. Posting from my phone, it could've messed the link up.
Anyway, it's been posted so many times that I'm sure juggs has seen it at least once or twice.
Again:
https://dreager1.files.wordpress.com/2012/06/abomination_vs_thor.jpg
He does wield it, but he didn't strike Blonsky with it. It was a simple punch.
That's it. Just 2 panels. Thor fans loved to repost it at least a dozen times a day to piss Hulk's fans off. Not long ago Marvel released some book with an untold tale, battle between Thor/Abom. Blonsky gave Thor a run for his money that time, but still got beaten in the end. Lightning/flight combo or something akin to that, not via pure hth means as Abom was too tough.
No, I don't think so. It doesn't work like his Belt of Strength or anything. Striking power is better with Mjolnir of course (obviously, hitting with an indestructible mallet will do more damage than with your fists), but he doesn't suffer any physical attributes nerfs while not equipping it. Thor even calls the hammer "just a tool".