40v toothed belt lose tension?
 

What would cause the toothed belt to lose its tension where the 2 idler pulleys are?

A bad tensioner?

The 40V does that. Depending on where it stops when you turn it off, the crank can bounce backwards from the compression of the next cylinder to fire. When the crank goes backwards, it loosens off the tension on the belt. As soon as you start it again, the belt tightens up and its all fine.

Interesting..... I did not know that. So no worries then?

The reason why I ask, I had a buddy come to help guide me with getting the engine to TDC and mark everything before taking the timing belt off. I took of the toothed belt covers and he noticed there is a fair amount of slack which is reason why I didn't do anything else after taking the timing belt covers as there was some concern with the slack. Which is why I asked.