The chain sprocket does not move but the moter runs

The chain tensioner is possibly bad. Here's a youtube on the subject:

https://www.youtube.com/watch?v=6NKuOM9pQNk

There is a clutch behind the metal housing where the chain sprocket at the engine end attaches to the chain . There are wear parts with springs on them that have to be changed. ChainSaw Shed Chain Saw Parts for Wen Wagner Brand Chain Saws Chains Bars... You can get parts here.

Probably the shaft on the sprocket has sheared off.

Knox Knolls Outdoor Power Equipment
Springfield, IL 62704
www.knoxknollsope.com

check to see if the chain is on the sprocket to do this you will probably have to remove the side cover on the saw if chain is on sprocket and still will not move then you may have a sheared key in the key way if this saw has one, if it does you should be able to see the key way on the end of the shaft coming out of the motor. there should be a nut that holds the sprocket in place if that nut is loose and the shaft is splined instead of having a key way the the sprocket could slip while the motor is turning.

The chain may have come off the sprocket.
There are 2 nuts about an inch apart down just past the bar which hold it in place.
Remove the 2 nuts, take off the cover which they hold in place and the bar and chain will loosen.
Check that the teeth on the inside of the chain are on the sprocket. Pull the chain tight against the sprocket and move it. Check that the sprocket turns. With the chain set in the sprocket replace the bar, chain and cover and try turning it again by hand. If it doesn't turn don't try to start the saw as you'll do damage.

If the chain was on properly and it still won't turn the clutch may be burned out. However the fact that you couldn't turn it by hand suggests that the chain was off the sprocket.

This is an unusual problem but there may be a reason. One reason is that a chain does not run as smoothly as a belt. Chains vibrate, badly. You didn't mention if the rear wheel was moving. As long as the rear wheel isn't moving, at least the adjustment isn't changing. You could use a nylon lock nut on the adjuster bolt, a "prevailing torque nut" or simply two nuts jammed against each other. Another problem could the "concentricity" of the sprocket. With the bike off the ground, roll the rear wheel and check for tight spots in the chain. When the chain goes tight, notice the position of the wheel. The hole in the center of the sprocket may not be concentric with the outside diameter of the sprocket. This could be applicable to the front sprocket as well.

Good Luck
Steve

There is a one way clutch that grabs onto a smooth cylinder on the side of a large gear inside the motor. The smooth barrel surface is on the side of what Honda calls the "starting sprocket". A chain connects the starting sprocket to a smaller sprocket that has the starter spline plugged into it. To replace this you will have to unbolt the motor and at least rotate it far enough to remove the rear cover. The chattered surface does not allow the three small barrels of the starter clutch to grab and turn the motor over. The sprocket runs about $70 and the gasket runs about $38.

Does the sprocket drive shaft turn when the sprocket does not? If so, look for broken coupling between the shaft and the sprocket. If the output shaft doesn't turn, then suspect a damaged (probably plastic) gear within the gearbox. Hope this helps!

Check the chain drive sprocket to see if it moves when the motor runs. If not, there may be a sheared key between the shaft and sprocket or the teeth on the sprocket are badly worn off. Hope this helps!

If the motor is working but the chain does not move you must remove the cover on the motor and check to see that the chain is on the sprocket. If the chain is on the sprocket and the sprocket is not moving but the motor shaft is moving then the sprocket must be retightened onto the motor shaft.