4 stroke engines vibrate more than 2 strokes. I'm not sure if you are saying you Broke the engine mounting screws?

It should not vibrate this much to break mounting bolts. I would look to the propeller balance.

If propeller is balanced, I'm not sure what else it could be. The engine will vibrate a slight amount more when has a setting too rich.

The 110 is actually quite smooth compared to the larger engine like the 140's. The 160 and 170 are much smoother than the rest of the engines.

But the 110 is not a bad vibration motor.

Troy Newman
Team YS Performance