Snapper 28in Rear Engine (Model #2811523BV) Blade spins slow

[bigj82nd]

I own a Snapper 28in rear engine (2011) with the 11.5HP Briggs and Stanton.
Last year while mowing, I managed to hit a root. A root that I have made it a point to cut around for the past 5 year. Boy did I hit it. Ben the blade, the spindle and tore the mower deck to hell.
I trailed the mower back home and began sourcing the parts. Acquired a new deck and spindle. But while I had it apart I decided to replace the rear boots on both side and a new clutch. Why stop there, I also replaced the belt.
I have taken good care of this mower, always garage kept, new spark plug, fuel filter, and oil change every year before storing it for the winter. Also, never ever used ethanol fuel.
This was my project but not one I dedicated alot of time to.
Once I got it back together, I notice a good deal of slack in the belt and that the blade was not spinning at its normal RPM. I adjusted the belt to 1in at its closest point with lever engaged. But the RPM on the blade is still low.
I am thinking that I have not tightened the bolt to the pulley enough. Do you have any thoughts or suggestions?

I am stuck, please help.

 

[bertsmobile1]

Remove the spark plug lead
Engage the belt and turn the blade by hand
If the belt has enough tension on it you should be able to turn the engine over by turning the blade
If not, watch the pulley to see if the pulley is in lock step with the blade
Be careful and wear gloves because a backwards flip from compression alone can give you a nasty cut .