Mowing BX2350 mower belt vibrating - normal?

[newcountry]

I have been the one person mowing for the past, Oh fifteen years, but today my lovely wife wanted to mow. I was conflicted -- frees up time for me to do other projects, but also introduces her to the wonder of tractordom. Visions of waiting for tractor time ran through my head. In the end I relented --she was off and running in no time.

Now to my question-- while I was watching her mow I noticed the belt vibrating quite a bit (this is the part of the belt that runs along from the back of the left pulley to the back of the right pulley). I had her stop and inspected the belt and the tensioner and couldn't find anything wrong. I let her continue for awhile then I finished up to get done before the rain started (got 'er done in the nick of time!! ). I could feel nothing and couldn't tell any difference with cutting. Am I missing anything, or is this just a normal part of moving parts?

 

[Volfandt]

It's normal, as long as it's not rubbing on anything. They jump around pretty good, especially on that long back run between pulleys.

 

[art]

Different loads on the blades will also cause the belt to tighten against idler.

 

[newcountry]

Thanks Guys!

It's probably always been that way, I've just never had the opportunity to observe the mowing until yesterday.