Chain locks up, smoke from clutch, chain and bar suddenly super-tight

[Pilgrim1]

Hi,

I've used a Husqvarna 450e for several years to cut many cords of firewood, although I'm certainly no expert. Recently I've noticed that it seems to have lost power, it stalls more easily, and sometimes the chain gets tight and doesn't spin freely.

Today it got worse. I removed and checked the chain and bar, but I didn't see a problem. Everything moves freely when disassembled and then also when reassembled. I then used it for a minute, and the chain got loose, so I tightened it appropriately. Soon after resuming cutting, the chain stopped, and there was smoke from the clutch when I tried to run it. When I checked it, the chain was *super* tight. It was so frozen up, I couldn't even loosen it with the adjustment wheel.

I repeated this a few times, and each time it locked up sooner. I tried a different chain, and managed to finish the cut, but it seemed to getting harder to spin.

What should I check? Or what photos would help?

Thanks,


Luke

 

[pioneerguy600]

Chain stopping is likely clutch and drive sprocket related, that includes the bearing between the clutch and shaft should be checked. The clutch shoes slipping causes a lot of heat. If the clutch is slipping then it could be damaged or the sprocket might be worn badly. The chain just might not be getting enough oil and it is heating up enough to seize it in the bar groove. If you could post a pic of the drive, either sprocket or rim drive that starts a search for the real culprit.

 

[Pilgrim1]

Thanks for the reply. Can you point me to anything that explains how to check the things that you suggested?

Do any of these line up with the fact that the bar and chain become extremely tight, as if the chain was over-tightened by a gorilla?

Thanks.

 

[Big_Eddy]

Check your brake band too.
If your brake band is dragging (cracked, stuck partially on, dirt or sawdust packed behind it) then the friction on the clutch drum will heat it up and clamp harder on the clutch drum until it locks up.

And check the bar sprocket tip.

 

[cscltd]

I think your oiler is not working or there is no oil in tank
Start saw without bar and chain and see if oil comes out of oil port hole.
If there is, then check bar, it may plugged with dirt etc where oil goes on through the bar

 

[Pilgrim1]

I think your oiler is not working or there is no oil in tank
Start saw without bar and chain and see if oil comes out of oil port hole.
If there is, then check bar, it may plugged with dirt etc where oil goes on through the bar

cscltd,

There is oil in the tank. Thanks for the specific steps to check if it's getting to the chain. I'll have a look.


Luke

 

[Pilgrim1]

Check your brake band too.
If your brake band is dragging (cracked, stuck partially on, dirt or sawdust packed behind it) then the friction on the clutch drum will heat it up and clamp harder on the clutch drum until it locks up.

And check the bar sprocket tip.

Thanks. How would I check the brake band? It seems to function correctly when the saw it running or off. I didn't see a crack, but I will look again.

The bar tip sprocket spins freely.

 

[irhunter]

If you could post a pic of the drive, either sprocket or rim drive that starts a search for the real culprit.

+1 for several pics.

Did you confirm oil is flowing out of the port (bar and clutch cover off)?

It is easy to miss packed-in saw dust/crud in the bar grooves and bar sprocket. You need to be able to actually see the bottom (steel) of the grove. I would soak the bar sprocket in something like Diesel, and blast it out with air (don't allow the sprocket to spin when blasting).

Sometime soon, you'll want to look at the clutch bearing. In case you don't have them, I PMed you the shop manual and IPL.

Roy

 

[oldbuzzard]

Hi,

I've used a Husqvarna 450e for several years to cut many cords of firewood, although I'm certainly no expert. Recently I've noticed that it seems to have lost power, it stalls more easily, and sometimes the chain gets tight and doesn't spin freely.

Today it got worse. I removed and checked the chain and bar, but I didn't see a problem. Everything moves freely when disassembled and then also when reassembled. I then used it for a minute, and the chain got loose, so I tightened it appropriately. Soon after resuming cutting, the chain stopped, and there was smoke from the clutch when I tried to run it. When I checked it, the chain was *super* tight. It was so frozen up, I couldn't even loosen it with the adjustment wheel.

I repeated this a few times, and each time it locked up sooner. I tried a different chain, and managed to finish the cut, but it seemed to getting harder to spin.

What should I check? Or what photos would help?

Thanks,


Luke

I use and repair chainsaws a lot and I have had a couple of different saws do the tight/loose thing on me. It drives me nuts because I can’t tell you that I ever definitely nailed down the cause. The latest offender was an Echo 620 but I’ve also had it happen on Stihls. I think it is related to the bar not being properly aligned with the sprocket (rim sprocket) and then not cinched down enough allowing it to shift. At least checking the alignment when reassembling and then tightening the bar hard cured (I think!) the problem.
The other related issue on a Stihl 261 was the clutch drive end of the crankshaft had actually been worn to a smaller diameter by a chain brake popping on. This let the clutch wobble.

 

[ZeroJunk]

Should be a E clip that holds the clutch drum on. Take it off with screw driver or needle nose .
Clutch drum should just slip off. Check the bearing.

If the drive links get burred from a worn clutch drum gear, or chain coming off and banging the chain stop , or using the wrong chain for the bar accidentally it will stop everything .

 

[Jasonrkba]

Make sure the bar matches the saw and it is in fact oiling. Sounds like a no oil situation like stated above.

 

[irhunter]

Should be a E clip that holds the clutch drum on. Take it off with screw driver or needle nose .
Clutch drum should just slip off.

This is an outboard clutch saw.

I agree that looking at the bearing is a good idea...but, getting to it is a tad more complicated.

Roy

 

[Gord404]

might be that your chain is not the right size drivers for that bar, slide ok when cold but tighten up when being used- too wide and your bar will have it written on it what size driver is called for. - before you tighten down the nuts make sure you lift the saw with the tip of the bar on something solid so it pushes it up

 

[PV Hiker]

Just saying. The more we see the better the help will be.

 

[Philbert]

Look in your Owner’s Manual (download a PDF copy if you don’t have one) how to remove the clutch, clutch drum / sprocket, and clutch idler bearing.

Then take clear, close photos, and post here.

These are wear components, like the brakes, battery, muffler, etc., on your car.

If you’ve used your saw for several years, and are not familiar with these, there is a good chance they are due for attention or replacement.

Philbert

 

[Philbert]

As far as the nose sprocket on your guide bar, the sprocket should rotate freely, and the chain should be held slightly away from the bar, in order for the sprocket bearings to do their job reducing friction.

If the chain tie straps are actually touching the bar at the nose, the sprocket is worn out and needs replacing.



Philbert

 

[buzz sawyer]

Hi,

I've used a Husqvarna 450e for several years to cut many cords of firewood, although I'm certainly no expert. Recently I've noticed that it seems to have lost power, it stalls more easily, and sometimes the chain gets tight and doesn't spin freely.

Today it got worse. I removed and checked the chain and bar, but I didn't see a problem. Everything moves freely when disassembled and then also when reassembled. I then used it for a minute, and the chain got loose, so I tightened it appropriately. Soon after resuming cutting, the chain stopped, and there was smoke from the clutch when I tried to run it. When I checked it, the chain was *super* tight. It was so frozen up, I couldn't even loosen it with the adjustment wheel.

I repeated this a few times, and each time it locked up sooner. I tried a different chain, and managed to finish the cut, but it seemed to getting harder to spin.

What should I check? Or what photos would help?

Thanks,


Luke

Had this exact thing happen on a 268. The oil hole on the bar kept getting plugged and no oil to the chain. I cleaned the mounting area, oil hole and bar slot real good and problem stopped.

 

[Old2stroke]

The other related issue on a Stihl 261 was the clutch drive end of the crankshaft had actually been worn to a smaller diameter by a chain brake popping on. This let the clutch wobble.

Should never happen if the drum bearing is good and lubricated.

 

[Okie]

You need to immediately stop trying to put the saw to work. (and fis the issue)

You say the clutch area smokes. I've seen this happen and the OP would just keep on trying to use a saw and eventually get so hot at the clutch drum area that it would heat bake and ruin the case behind the clutch drum. (not a fun job getting another case and transferring all the parts) You say the chain get tighter.
Usually if a chain is not getting oil is will loosen.
Check the clutch drum/brake area. See if the brake band is heat colored.

 

[HarleyT]

pics!