Stihl low on power

[TNhobbyfarmer]

My 025 Stihl chainsaw seems to be low on power. I am having problems cutting logs that it used to zip through. I put a new chain on and it's still not cutting well so it's not just a dull chain. Even though it starts easily and sounds like it always has, the engine appears to be running hot. There is smoke coming from under the chain cowling. I am thinking about one of two options. Either take it too a service center and have it serviced or just get a new one. I am worried about a large repair bill and not being satisfied with the results and then going on and getting a new one anyway. What would you do?

 

[randy41]

is the oiler working properly?

 

[KiwiBro]

Was it going fine when you first started to use it that day but just seemed to de-power after a little while?

 

[tcartwri]

The muffler is probably fouled with oil.

 

[BleedingOrange]

How fresh is the gas ?

 

[murphy1244]

The muffler is probably fouled with oil.

Yep, soak in in gas overnight.

 

[KiotiJason]

Replace the fuel filter, air filter and the spark plug. Also as suggested check the muffler, you could also take the muffler off and check to see if the Pistons scored. But definitely put new fuel in it as you might have a bad batch. (Make another batch)

 

[ruffdog]

Chain brake hanging up?

 

[rekees4300]

My 025 Stihl chainsaw seems to be low on power. I am having problems cutting logs that it used to zip through. I put a new chain on and it's still not cutting well so it's not just a dull chain. Even though it starts easily and sounds like it always has, the engine appears to be running hot. There is smoke coming from under the chain cowling. I am thinking about one of two options. Either take it too a service center and have it serviced or just get a new one. I am worried about a large repair bill and not being satisfied with the results and then going on and getting a new one anyway. What would you do?

Chain oiler is my guess. Bar gets hot and expands causing chain to become so tight that engine can't turn it.

 

[mfreund]

Make sure you have 2 stroke oil in gas.

 

[s219]

Lots of simple checks you can do yourself are listed here -- all good advice. Eliminate the simple problems before deciding whether to invest in a repair or new saw.

How many hours are on this saw?

 

[TNhobbyfarmer]

Thanks to all that responded with good tips and advice. In response to a few thoughts mentioned here, the gas being used (non ethanol) is fresh and properly mixed and the spark plug and air filter have been recently serviced.

The more I have read has lead me to think the problem is the chain oiler. I looked at a couple of youtube videos regarding replacing the pump and associated worm gear. It looks like a fairly straight forward fix that I will attempt to do myself. The parts aren't too expensive, and if I somehow screw the repair up, I can always take everything to a qualified technician for help. Don't ask me why I know about this option. Hint, past experience.

Anyway, thanks again for the responses. I'll give a final report on how this all works out. If all else fails, I can buy a new saw.

 

[BethelHntr]

When you replaced the spark plug was the electrode color black, white or tan brown, The carb hi and low adjustment screws have been known to move under vibration, This could cause low performance along with all the previous suggestions.

 

[s219]

I'd check to make sure all the oil passages are clear before digging into the oiler pump. The passages can clog up easily.

 

[KiotiJason]

Run the saw at WOT with the tip near the ground or some carboard and see how much bar oil is getting flicked out of the tip. But in any event just by looking at the chain and the heat of the bar you should definitely know if it's not oiling.

 

[RalphVa]

I'd doctor the gas/oil mix with Seafoam. Sounds as though your mixture has leaned up at speed but okay at start/idle.

Seafoam has gotten me out of several carburetor tear downs.

Ralph

 

[TNhobbyfarmer]

I'd check to make sure all the oil passages are clear before digging into the oiler pump. The passages can clog up easily.

Where are the oil passages? Easily accessible?

 

[TNhobbyfarmer]

Run the saw at WOT with the tip near the ground or some carboard and see how much bar oil is getting flicked out of the tip. But in any event just by looking at the chain and the heat of the bar you should definitely know if it's not oiling.

WOT? Don't think I ever heard that one. I'm sure I'll go "duh" when you educate me.

 

[Coyote machine]

Verify the oil passages by blowing out everything with compressed air. Then make sure there is oil shooting off the bar tip. Then, if there is no oil being dispersed look at rebuilding the oil pump.
Also change the in tank fuel filter.

 

[gsganzer]

WOT? Don't think I ever heard that one. I'm sure I'll go "duh" when you educate me.

Wide open throttle. Lay out a piece of clean cardboard and hold the bar tip very close as you run the saw WOT. You should see a good spray of oil flinging off the bar tip.

Also, check the spark arrester screen mounted on the muffler exhaust. Running too rich or poor 2-cycle oil will plug the screen. I only use stihl or husky oil mixed with premium gas only.

Remove the bar side cover and make sure you don't have chips/debris or weeds causing drag on the sprocket. Long weeds or grass can wrap up in there and bog things down.

If none of those are the culprit, take it in for a tune up.