Attempted to go for a ride today and immediately had problems. The biggest thing I noticed right away was the sound. The ski seemed to shake just a bit, and the motor had a much lower muffled sound to it.

Self diagnosis notes:

- Last ran two days ago. Ran perfect, flushed when finished.
- Oil level is fine.
- Plugs are perfect
- Ski is bone stock
- Prop is clear of any debris. Although the ski seemed to shake just a bit, it was definitely not from something being jammed in the prop. To be honest, the ski might not have even been shaking at all. It just "felt" different with the low muffled sound.
- Was not moving as fast as it should've been at the different RPM levels I tested it at.
- Supercharger was rebuilt just 20 hours ago. Should be fine.

Any ideas what this could be?