Stihl 026 chainsaw - no power

[ejb]

I have a 15 year old Stihl 026 chainsaw...its been a great saw and seen a good amount of use...much more than an average homeowner I would guess, but not nearly as much as a logger.

It started running badly this year so I changed the tank to fresh gas, put a new chain on it (which I usually do every 1-2 years) and cleaned out the air filter and new spark plug(which was pretty bad).

Starts up fine now, accerelates fine, but when under power it smokes like crazy and has not much power at all...can barely cut a tree without a gas mask on /forums/images/graemlins/ooo.gif

My guess is a carb adjustment...but which one? With these symptoms, is it getting to much gas, or not enough? starved for O2?...is it asking too much of a 15 year old saw, or do they pretty much run forever?

 

[SkyPup]

They run forever.

I have a 25 year old 026 Pro that has seen unreal hours of heavy duty use. I tried to trade it in on a new 028C this year but the folks at the Stihl shop told me it would be a crime to trade it in as they last forever, so I kept it and got a new O28C too!

I suggest that you make some new fuel using fresh gas and full synthetic 2-stroke oil, and gap the spark plug.

You'll need a tachometer to set the high rpm carb setting and the low rpm setting (make sure the air filter is clean or new too).

If that does not work, do a compression check on it, it could need new rings if they are worn or have lots of gum sticking on them, howver a fresh tank of gas and good synthetic two stroke oil will clean that up.

 

[slowrev]

Muffler some clogged up ? Will cause power loss and smoking.

Ben

 

[RobertN]

You've checked some of these, but here's my list /forums/images/graemlins/wink.gif

Dump the tank
replace fuel filter in the tank and check fuel hose
refuel with FRESH PREMIUM gas and good quality mix
Clean or replace the air filter
Put in a new plug; check gap before installing
Remove the muffler
Clean the muffler
Clean and/or replace the spark arrester screen

Blow out the cooling fins and stuff whle covers are off too...

What mix are you using, and at what ratio? Stihl and Husky both make excellent 2-stroke mix. Mix as noted on the container; Husky mix is formulated for 50:1. I only mix a gallon at a time. I always use premium(these are high perforamnce 10,000rpm motors after all). I buy the little bottles of Husky oil that are made for mixing one gallon. 2-stroke mix degrades after mixing with gas. Remember it's a 10,000rpm engine; degraded lubrication is bad for it. I know of motocross dirt bike racers that use thier gas with 12-24 hours. Longer than that, and they won't run it in thier race engines...

It sounds like you have old mix, or the mix is at too rich a ratio. Either that or the spark arrester is too clogged to run at high rpm. Or, a mixture of both problems...

You could mess with the high speed jet. Try turning it 1/4 turn either way and see if it clears.

Kits are availble for carbs like that. I got one for an older Husky for about $15. Wound up replacing the carb; it was only about $75.

 

[DrRod]

RobertN brings up an oft overlooked point -- chain saws need high octane gas. I have an 026 and the manual says 91 or higher. I'll bet only 1 in 100 users has ever read this or follows it.

 

[MikePA]

<font color="blue"> chain saws need high octane gas. </font>
I just bought a Stihl string trimmer (4 cycle engine that uses a gas oil mix) requires premium gas, too. My dealer made a point of mentioning this several times.

 

[bczoom]

ajb,

Any update/fix?

If we're taking bets, I'm going with slowrev (and others) that think the muffler may be clogged.

One other thing that I didn't see mentioned was to avoid using 2 cycle oil that is made for marine applications. Don't recall exactly but do recall that it's a no-no.

Brian

 

[PineRidge]

My Stihl started doing the same thing so I took it into the shop for repair. There was a stainless steel screen in the muffler that was plugged. It now runs like new. Check to see if yours has the screen and make sure it's clean.

 

[RobertN]

Air cooled 2-stroke mix and water cooled mix are different because of the higher heat involved with air cooled engines.

A few years ago, I had rode rode my dirt bike on a Saturday. I mixed premium gas with a high grade racing 2-stroke mix. I had a gallon or two left over at days end. Went wood cutting the next day. Decided to use the gas mix from the dirt bike. My saws would start, idle, and rev without a load. As soon as I started to cut, no power! These were good running saws, using a premium motocross racing mix /forums/images/graemlins/shocked.gif

I gave up, dumped the tanks on the two saws. Went and got fresh premium gas, and mixed with chainsaw mix. Both saws ran great and cut like crazy.

Go figure /forums/images/graemlins/crazy.gif

 

[SkyPup]

I been using Amsoil's Full Synthetic 2-stroke motor oil in my three dirt bikes, six chainsaws, two weedeaters, and two outboards for years now, works great in everything.