Chainsaw?

[demarpaint]

I have a 20" Craftsman chainsaw, probably about 12-15 years old. It is difficult to start but runs fine, I'll address that shortly, I hope. Here's the issue:

The bar and chain are properly lubed and adjusted, however once the machine gets hot with use the chain becomes very tight, no slack at all. It remains that way even when it cools off. I re-adjust it and have the same problem. I am going to try a different bar and chain, I'm thinking the problem is with the bar itself. I am familiar with the saw and how to install the bar and properly adjust the chain. I was wondering if anyone else encountered this issue and if it is the bar that is the problem? TIA.

 

[ironman_gq]

Only time I've had them tighten when they warm up is when the oiler isn't doing it's job properly, if anything they always get a little looser when the chain heats up. Are you sure the tensioner isn't moving when you cut wood?

 

[demarpaint]

Originally Posted by ironman_gq
Only time I've had them tighten when they warm up is when the oiler isn't doing it's job properly, if anything they always get a little looser when the chain heats up. Are you sure the tensioner isn't moving when you cut wood?

The oiler is working well, and the tensioner isn't moving, those were the first things I checked. You are correct, with use the chain might get more slack, this is the complete opposite. I just checked it as it cooled off the chain is tighter than when I started cutting wood earlier, but not as tight as when I first turned it off. I am going to try and different blade and bar after lunch and see what happens.

 

[MParr]

Most likely the bar is worn out.

 

[InhalingBullets]

Change the BAR and Chain.

 

[Langanobob]

There is a little bit of up and down play in the bar tip when the adjusting bolts are loose. Make sure the bar tip is up as far as it will go when tightening the bolts. Worth a try.

 

[Donald]

flip the bar upside down.

 

[doitmyself]

Check your sprocket/clutch assembly for wear also.

Is it actually getting tighter, or is it just binding up? There is a difference.

 

[JLawrence08648]

I agree with several on here, clean the inside of the bar rail, check the wear on the teeth of the sprocket, flip the bar upside down if possible, check the oiler to ensure it's working. Readjust the chain after hot giving yourself just a hair crack of space and then see. I like when hot no space but it should roll with moderate effort. Pick up the bar tip when adjusting the chain. Make sure the hole in the bar is in the adjusting screw piece. Make sure that piece is not rounded and is slipping. Make sure the adjusting screw threads are good. Use only bar oil.

 

[BrocLuno]

Roller tip, 1/8" slack pulled up in the middle of the bar cold. Hard Nose tip, 1/4" slack in the top center.

Roller tip greased with pencil gun every tankful.

All bars tightened with the nose on something firm and the bar up as snug as possible. If not it will tighten as you use it.

New bar and Stihl or Oregon "Oil Rite" chain with the carry holes in the drive links. Real tacky thick bar oil, not motor oil. Oil the bar with a slug out of the bottle before you start cutting on new to help it bed in.

Are you cutting green or dry wood? Green normal bar oiling should be fine. Dry old wood, you need to add extra oil as the saw dust sucks it away way to fast. Cut, splash lube on, roll the chain around with a blip until wet all over cut some more.

High resin wood like dry pine and fir and any creosoted wood will need a stream of kerosene shot into the cut as you saw from an old oil can. They can gum up a bar quick ...

 

[andyd]

My Stihl is on its 2nd bar only because I pinched it in a felling gone bad. As the components wear, they get looser. As the chain heats up, it gets looser. The only time I've had a chain get tighter is from wood getting in the bar or sprocket. Possibly a lack of oil, but that would cause noise and smoke. I'm clueless. Please post your progress. Wild guess is the bar tip is seizing.

 

[demarpaint]

Originally Posted by Donald
flip the bar upside down.

Thanks for the flip the bar tip. It must be the bar. I flipped the bar, I usually do that when I sharpen the blade. Flipping the bar made it happen faster, and it was so tight when hot that it was able to bog the engine down trying to spin the tight chain. I switched to another bar and chain combo, 18" which is all I had and it worked.

When I have some free time I will address the cold starting problem......

 

[spasm3]

Probably the bar and the chain.

But its important to check the sprocket on the saw. They can get worn in the middle and that cause tension problems.

 

[HangFire]

Originally Posted by BrocLuno
Real tacky thick bar oil, not motor oil. ...


I had a gallon of Poulan bar oil that was thicker than usual a couple of years ago. Gave me no end of problems, kind of like you describe. Lubed, but slow running, tight, hot.

Switched back to normal thickness Stihl, problems went away.

Thinned Poulan with kerosene, problems stayed away.

 

[demarpaint]

Originally Posted by BrocLuno
Roller tip, 1/8" slack pulled up in the middle of the bar cold. Hard Nose tip, 1/4" slack in the top center.

Roller tip greased with pencil gun every tankful.

All bars tightened with the nose on something firm and the bar up as snug as possible. If not it will tighten as you use it.

New bar and Stihl or Oregon "Oil Rite" chain with the carry holes in the drive links. Real tacky thick bar oil, not motor oil. Oil the bar with a slug out of the bottle before you start cutting on new to help it bed in.

Are you cutting green or dry wood? Green normal bar oiling should be fine. Dry old wood, you need to add extra oil as the saw dust sucks it away way to fast. Cut, splash lube on, roll the chain around with a blip until wet all over cut some more.

High resin wood like dry pine and fir and any creosoted wood will need a stream of kerosene shot into the cut as you saw from an old oil can. They can gum up a bar quick ...


Thanks for all the replies. I was cutting a mix of wood, some fresh, some seasoned. I'm using the same bar oil I always use. Changing out the bar and chain seems to have solved the problem.

Tomorrow or Friday I'm going to have to take off the carburetor, and rebuild it. The engine won't start if it sits overnight w/o a shot of ether or carb cleaner no matter what.

 

[Finz]

Consider a replacement carb vs rebuild. Pricing may be on par and a heck of a lot easier. Carb for chainsaw that old may be in the $15 - $20 neighborhood...?

Not to add to your workload, but also consider replacing the fuel lines... another inexpensive preemptive measure that can save yourself some heartache. Like myself, you may need an extra long needle nose plier to reach into fuel tank.

Good luck

 

[demarpaint]

Originally Posted by Finz
Consider a replacement carb vs rebuild. Pricing may be on par and a heck of a lot easier. Carb for chainsaw that old may be in the $15 - $20 neighborhood...?

Not to add to your workload, but also consider replacing the fuel lines... another inexpensive preemptive measure that can save yourself some heartache. Like myself, you may need an extra long needle nose plier to reach into fuel tank.

Good luck


Thanks. I'll replace the fuel lines with the carb. IIRC I have a carb in a small box in the garage somewhere. I've had good luck in the past with these machines taking the carbs apart and giving them a good cleaning, I might try that first. There is a tiny circular screen in some of them that gets a bit of dirt in it and that's all it takes to screw everything up.

 

[Lubener]

When I have had oiling issues causing the chain to heat up, the chain always loosened not tightened. Heat expands. I would look for a worn out bar assy.