LOGTH2448T PTO throwing off new belt

I have a Husqvarna LOGTH2448T that belongs to a friends dad. My friend was mowing and the belt came off.
The bearing in the idler pulley went out and the pulley came off.
I dropped the deck and found the bad pulley and a bad crack in the belt so I replaced both.
All other bearings were good and smooth so I lubed everything.
I reinstalled the deck with the new belt, started the engine and engaged the PTO. The belt immediately came off the engine pulley.
The belt was off when I got the mower so I didn't see how it went.
Here's two pics. The red line on the pic is how I believe it should be. The idler pulley is missing in the pic.

Update: The mounting surface on the new idler pulley was a little longer than the old pulley and the pulley was sitting a little higher and pulling the belt off.
I ground it down until it set at the same height as the old pulley and it works fine now.

Excellent.
FWIW the internal spacer on most idlers is a light press fit.
It is common to find the replacement is not the same so I have been pushing the old one out & fitting it into the new pulley for a long time.