General Product Question
What is going on with my chain?
General Product Question posted July 16, 2018 by Russel Hawkins
61 Views, 3 Comments
Question:
What is going on with my chain?
Details:
I have a 240 Chainsaw. I bought a brand new bar and chain for it and as soon as I get it all ready to start cutting, it feels like the brake is on and then when it starts turning the chain goes from super tight to extremely loose back to tight and after its starts moving it comes off the bar. I have no idea what is going on.
Answer
Russel,
Is your chainsaw one of those "EZ - tensioners" ?
I would remove the clutch cover and double check that the chain is fitting into the drive sprocket properly ? I believe the Model 240 only comes with a drive sprocket with one pitch, maybe 3/8 pitch. I would suggest checking your owners manual for the correct chain pitch. Then make sure that the drive sprocket, bar, and chain are all the same pitch. It is possible that someone in-advertently put a .325 pitch chain on the chainsaw, and you have a mis-match. All three parts Must have the same pitch (drive sprocket, bar, and chain).
I hope this helps, and please let me know If I can be of further assistance
Karla
PS. I am Not a Husqvarna Representative or a Repair service, just an experimental chainsaw person
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Russel,
I just double checked your owners manual for the model 240, and It does indeed come with a choice of either a .325 pitch chain or a 3/8 pitch chain, so you most likely have a mis-match. Confusing to some consumers, and thinking that they can just change the pitch of the chain. But this is NOT true, In Order to swap the pitch of a chain you must replace all three parts (Drive Sprocket, Bar, and chain). Changing just one of these parts to the wrong pitch will cause exactly the symptoms that you have. SO you need to verify, which pitch you have (.325 or 3/8) and then make sure all three parts match that pitch.
Again, I hope this helps
Karla
PS. I am Not a Husqvarna Representative or a Repair service, just an experimental chainsaw person
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Russel,
Just a couple more thoughts: The reason I asked If you have one of those "EZ tensioners" , Is some times the little plastic gear inside the clutch cover becomes stripped or worn, and then when you turn the thumb knob tensioner, it really doesn't tension the chain properly, and you find yourself turning the thumb knob back and forth to try and get it tensioned properly, So If you have the "EZ" tensioner and it has a problem, I would recommend replacing it with the standard clutch cover that has the screwdriver adjustment. It definitely will fit, and my personnal opinion is I like the adjustment better on a standard clutch cover,
Finally, one more thought: I notice that you stated that you changed the bar and chain, so I am assuming you did this because it was badly worn and in bad condition, other than maybe you just wanted a new bar and chain. Anyhow If they were really worn, then you may also have a really worn drive sprocket. I have seen where the drive sprockets have gotten so worn that they created a deep groove into the drive sprocket, and sometimes this will create the symptom you are describing in your problem. The reason the symptom occurs is that once the drive sprocket has this worn groove, the chain will move axially along the drive sprocket or If you were looking at the end of the clutch shaft the chain will move in and out, as the end of the bar deflects during use trying to keep the chain in a straight alignment. So when the chain falls into the groove of the worn drive sprocket, it will feel loose, and when the chain moves out of this groove the chain will get tight. I have seen this on a number of occassions on worn drive sprockets. the fix is to replace the drive sprocket. Another recommendation is to replace the Standard Drive sprocket with a "Power Mate" or similar drive sprocket which has the separate replaceable Rim sprocket. This type of drive sprocket allows the Rim to move axially keeping the chain in straight alignment with the end of the bar. Also, as you get a lot more use from your chainsaw in the future, the "Rim" sprockets are very reasonable, like maybe $5.- in small quantities, so that every time you have worn out a chain or two, you can simply replace the "Rim". Just my two cents !
Again, I hope this helps and please let me know on this forumn, what you discover to be the problem. Sorry to be so wordy, but just trying to provide lots of information for you.
Karla
PS. I am Not a Husqvarna Representative or a Repair service, just an experimental chainsaw person
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