What to check when chainsaw chain won't move freely?

Question

I was using a Husqvarna 440 chainsaw and ran into some trouble. I managed to get it stuck in a log. Once I got it out I had to adjust the chain tension, but then everything was OK again. A few minutes later, the chain derailed on me. I was able to put it back on but it kept sticking. I wasn't able to get it at the right tension without it being almost impossible to turn by hand. Here is what I checked/tried...

1. There is plenty of bar oil.
2. The chain brake is disengaged, and it was disengaged when I took the cover off.
3. I cleaned out the grooves in the bar so I know there is nothing preventing the drive bars from seating.
4. The sprocket at the end of the bar moves freely.

If it helps to further diagnose the problem, this is what I have been doing:

1. Verify chain brake is off.
2. Remove cover.
3. Install bar.
4. Install chain, starting at drive sprocket and moving outwards along the top of the bar.
5. Replace cover, tighten the nut barely fingertight.
6. Adjust tension screw until chain is tight enough that I can only pull it about 3/4 of the way out of the track.
7. Tighten cover nut all the way.

When I get to step 6 above, the chain turns with my hands but it's hard to move. At step 7, when the cover is fully tightened on, it won't move at all.

Thanks for any tips on what to check. I suspect that the chain might need attention but I don't know where to start with that. Hoping to avoid a trip to the repair shop if I can fix it myself.

Answer 1

Depending how it got stuck pinching may have closed up the channel in the edge of the bar that guides the chain at one or more spots. That would be cured with a new or different bar.

You might be able to spot the pinched section by sighting along the bar without the chain, or feel it by running the guide part of one tooth around the edge of the bar.

If the bar has a nose-sprocket, those can also get pinched or bound up.

A somewhat less likely cause would be if a section of the chain got its guide-parts bent with respect to the rest of chain, and is binding because it hits one side of the groove as the neighboring chain parts hit the other. A new/different chain would solve that one.

Answer 2

Solved it. I had the chain brake accidentally engaged from removing the cover. An old pro fixed it in 2 minutes by reseting the brake. Rookie mistake!