A properly tensioned chain will optimize cutting performance. The tensioning rule of thumb for a concrete cutting chain saw is that a properly tensioned diamond chain must not be bowstring tight and can be pulled freely around the guide bar by hand easily without binding.

You should be able to pull the chain around the bar by hand - be careful to avoid sharp edges on the guide bar.

Chain Tension is looser than a wood chain.

If the chain is too loose, it could come off the bar, or it will allow the drive sprocket to spin without turning the chain, which can chew up the chain drive links. If the chain is too tight, a lot of the saw's power goes into turning the chain rather than into the cut. In extreme over-tightened cases, the saw may not be able to turn the chain at all. In addition, damage can occur to the bar nose and premature stretch may occur.

You should be able to pull the chain around the bar by hand - be careful to avoid any sharp edges on the guide bar.

Proper Chain tension should allow the top of the links to hang just below the bar.

Before cutting, check for proper tension by pulling the chain around the bar by hand. If you cannot easily pull by hand, the chain is too tight and needs to be loosened.

Always rotate chain away from the wall-walker. The wall-walker is located in the front of the power head and is positioned just above the top of the guide bar.

When rotating chain, be careful to avoid any sharp edges that may have developed on your guide bar from normal wear.

To tension the chain:

1. First loosen the side cover nuts

2. Then hold the nose of the bar up

3. Use a screw driver to turn the tensioning screw clockwise until the chain drive links are hanging just below the guide bar and are just beginning to enter the bar groove

4. Continue to hold up the nose of the bar and firmly tighten the side cover nuts, (20ft-lbs).

5. Remember, it's the side cover nuts that hold the bar in position.

This ICS video shows proper chain tensioning.