# Stihl 026 hard to start, bogs down easily



## JRP3 (Sep 23, 2008)

Picked up a used 026 with 18" bar.  At first it wouldn't start so I took off the air cleaner which was all plugged and cleaned it up and got it going.  It still takes a while to get it running when cold.  It has a torn black rubber button or plug on top which I thought might be a compression release but it doesn't move when I push it.  I put a new chain on it and it revs up nicely but a little way into a cut it bogs down badly, I can lean harder on my Makita UC 4000 electric.  This is in a 12 inch log which I would think should be no problem for it.  What do you think, too lean maybe?


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## BJ64 (Sep 23, 2008)

I bet somebody along the way adjusted the hi and lo air adjustment screws out of whack.  That is what I would look at SECOND.  

First I would replace the spark plug unless you know it is good to eliminate that potential issue.  According to the mechanics at my saw shop, the spark gap area of the plug can still look good while the material in the white glass part of the plug goes bad.  I use NGK brand spark plugs.  

Next items I would check would be the little rubber lines that go to and from the carb.


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## JRP3 (Sep 23, 2008)

Yeah I was going to throw a plug in it, any idea of the gap?  Any idea what the rubber plug/button is in the top of the saw?  It looks like a screwdriver slot under the torn rubber.  The parts diagram I downloaded calls it a slotted nut and insulator.


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## kevin j (Sep 23, 2008)

I think the top deal is a mount for the plastic. if i recall right, there is some sort of groove on the pin/bolt, and the plastic has a rubber grommer that snaps into the hole in the plastic, then over the bolt/pin. Basically, snap on mount for the plastic. the grommet cracks and one end spirals outward.
I know mine had that poking out and I fixed it, just don't recall how. I can look tonight.

k


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## fishboat (Sep 23, 2008)

Check everything mentioned so far & then you might look for a can of Seafoam.  Use it as directed.  Two-cycles get carboned up after a while & this will make it run poorly(if the air-fuel mixture is messed up, even more so).  Seafoam will burn the carbon out..it'll produce lots of white smoke initially, but this will burn out.   Warm the engine up, hit it with Seafoam, let it sit, restart & run it hard for a while. 

I picked up a leaf-blower on ebay a couple years back.  It ran pretty much how you've described your chainsaw...no surprise the guy sold it (probably figured it was worn out).  I hit it with Seafoam a couple times & it's run great ever since.


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## bill*67 (Sep 23, 2008)

the plug you mentioned is supposed to have a hole in it. under it is the threaded nut w/screwdriver slot that holds down the top cover of the saw.


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## BJ64 (Sep 24, 2008)

fishboat said:
			
		

> Check everything mentioned so far & then you might look for a can of Seafoam.  Use it as directed.  Two-cycles get carboned up after a while & this will make it run poorly(if the air-fuel mixture is messed up, even more so).  Seafoam will burn the carbon out..it'll produce lots of white smoke initially, but this will burn out.   Warm the engine up, hit it with Seafoam, let it sit, restart & run it hard for a while.
> 
> I picked up a leaf-blower on ebay a couple years back.  It ran pretty much how you've described your chainsaw...no surprise the guy sold it (probably figured it was worn out).  I hit it with Seafoam a couple times & it's run great ever since.



That Seafoam is good stuff.  I put it in a 2002 Chevy one ton with one of those 8.1 liter jobs.  The smoke rolled for a while but it sure ran better after it was over.


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## fishboat (Sep 24, 2008)

In my fishing-boating days I used to run Seafoam through the engines once a year...before I put them away for the season.  I'd smoke out the neighborhood or landing for a couple minutes, but the engines ran like new afterwards.    Sometimes things are so bad you need two applications (I used two on the blower I picked up). 

A friend used a good amount of Seafoam on an older truck & it smoked so much that a neighbor of his called the fire department...they thought he lit his place up.


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## JRP3 (Sep 24, 2008)

wildbillx8 said:
			
		

> the plug you mentioned is supposed to have a hole in it. under it is the threaded nut w/screwdriver slot that holds down the top cover of the saw.


Yup that's what it is, I thought it was a push button with a hole worn in it or something.


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## WonderingWoman (Sep 24, 2008)

fishboat said:
			
		

> In my fishing-boating days I used to run Seafoam through the engines once a year...before I put them away for the season.  I'd smoke out the neighborhood or landing for a couple minutes, but the engines ran like new afterwards.    Sometimes things are so bad you need two applications (I used two on the blower I picked up).
> 
> A friend used a good amount of Seafoam on an older truck & it smoked so much that a neighbor of his called the fire department...they thought he lit his place up.



So this seafoam stuff works on outboards? Do you add it to the gas?


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## Joey Jones (Sep 24, 2008)

Whats does this Seafoam do? I have lots of stuff to put up for winter and was impressed with reference to seafoam. I live near a Napa store and they might have it...also a close by VIP.


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## polaris (Sep 24, 2008)

Seafoam is a carb/combustion chamber/valve cleaner. It is one of the few that works effectively and safely in two strokes. Napa does carry it. Seafoam is a top knotch product that can really put life back into some heavily gummed up, carbonized engines. (works wonders on diesels too)


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## WonderingWoman (Sep 24, 2008)

polaris said:
			
		

> Seafoam is a carb/combustion chamber/valve cleaner. It is one of the few that works effectively and safely in two strokes. Napa does carry it. Seafoam is a top knotch product that can really put life back into some heavily gummed up, carbonized engines. (works wonders on diesels too)



Thanks for the tip! This forum is great!


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## JRP3 (Sep 24, 2008)

Ok, threw in a new plug, gapped at .020, (though the old one looked ok, gapped a touch large at .025), same problem.  Took a close look at the fuel line from the tank and found some cracks.  No wonder it doesn't want to run, it's probably sucking in air.  I think a new fuel line will fix me right up, the saw doesn't look very heavily used other than that.  Looks as if it might be a pain to change, anyone know how far I need to break this thing down, any tips?


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## smokinj (Sep 24, 2008)

JRP3 said:
			
		

> Ok, threw in a new plug, gapped at .020, (though the old one looked ok, gapped a touch large at .025), same problem.  Took a close look at the fuel line from the tank and found some cracks.  No wonder it doesn't want to run, it's probably sucking in air.  I think a new fuel line will fix me right up, the saw doesn't look very heavily used other than that.  Looks as if it might be a pain to change, anyone know how far I need to break this thing down, any tips?


take your time and change the fuel filter why your at it


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## fishboat (Sep 25, 2008)

I'm not much for snake oils, but seafoam is actually one that I believe works well.  The directions on the can indicate you can use it in the crankcase as an oil additive, in the gas tank as a valve cleaner & stabilizer, or in the cylinders to clean carbon out of the head & rings.  I've only used it on cylinders.  Get the engine warm, spray seafoam into the carb until it kills out, let it sit 15-20 minutes, fire the engine up & burn out the smoke...repeat if needed.  

Supposedly you'll get the same result by adding seafoam to the fuel, but I think the cylinder approach is a little more to the point.

note: I edited out the "pour it in the cylinder approach" as this could be problematic if you leave too much in the cylinder...spraying in the carb until it kills works well & is generally safer from the engines point of view.


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## Joey Jones (Sep 25, 2008)

Good Stuff on the Sea Foam Product...Now how is it best used?   Sorry I'm just dumb about engine stuff?
JChang


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## JRP3 (Sep 30, 2008)

Still fighting with this thing.  New fuel line fixed the hard starting, now it starts right up, idles well, revs right up at first but still dies out after revving up, like it's running out of fuel.  Let off and let it idle a little then I can rev it again then it bogs down again.  I forgot to pick up a new tank pickup filter but took the old one off and tried running it without a filter but it still does the same thing so it's not the filter.  Anyone know the proper way to adjust the high side carb setting?
One thing that may or may not be relevant, the new fuel line had a larger diameter section where it goes through the hole in the fuel tank than the old line.  I asked the dealer about that and he said that's the way the new ones were and it would work fine.  I greased it up and got it in but I wonder if squeezing through the smaller hole might be constricting the hole in the fuel line and not allowing enough fuel flow?


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## eba1225 (Oct 1, 2008)

JRP,

Are you sure that it is starving for gas?  

My 028 is acting in a similiar fashion but mine is that it is getting overloaded with fuel I can tell by looking at the air filter which gets Damp-Wet after running(idle to med speed, repeated) for 1 min.  

Erik


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## JRP3 (Oct 1, 2008)

Hmm, never considered too much fuel.  What happens with yours if you hold it wide open?  Mine bogs down after a second or two.  Both my adjustment screws are at one full turn open.


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## eba1225 (Oct 1, 2008)

If I go full open it will bog down to the point that it may die.  Most times it does die but sometimes is does sputter along.

I am going to look at the muffler, try running without it to see if it guns any better.


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## JRP3 (Oct 1, 2008)

I might try that as well.


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## JRP3 (Oct 1, 2008)

Opened up the muffler and it's all clear, it's basically a metal can with a screen over it so I'm not sure what would clog it up anyway.
I'm about out of ideas, might have to break down and take it to the dealer  :-S  The piston looks really clean and I don't think the saw has seen that much use, maybe junk in the carb has something plugged?


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## kevin j (Oct 2, 2008)

sounds like a good carb cleaning is in order. Not that tough to do, and a skill you will use often in the future.
get the baseline stuff right first. carb clean, fuel lines, filter, plugs, and compression. sounds like you are almost there. 

k


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## JRP3 (Oct 2, 2008)

Yeah, probably, I'm just getting annoyed with this thing and want to cut something with it, not work on it.  I've done a number of carb rebuilds in the past, some were even successful  ;-)  nothing this small though.  I'm going to check the tank vent and the impulse hose first.


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## polaris (Oct 2, 2008)

JoeyJ said:
			
		

> Good Stuff on the Sea Foam Product...Now how is it best used?   Sorry I'm just dumb about engine stuff?
> JChang


   The best way to use Seafoam on a gas powered car/truck is to remove the brake booster line with the engine warm and running(or any vacuum line that evenly distributes to all cylinders). Slowly pour it into the line(the line is vacuum operated so it will suck it out). When engine dies let it sit for 20 min. or so. Restart and A LOT of smoke will come out. Repeat if needed. For diesels fill fuel filter canister and start. Shut it down right away and restart in 5-20 min. For two strokes mix in fuel/oil as directed and run a couple tanks of the mixture through. As another poster said I don't put much faith in snake oils but this stuff really works.


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## Adios Pantalones (Oct 2, 2008)

JRP- starting then dying when revved up could be a vacuum forming in the gas tank.  With nice tight sealed tubes etc- make sure that the vent in the fuel tank is not clogged up.


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## JRP3 (Oct 2, 2008)

I took the vent off, couldn't see any blockage, took out the screw in the end and the small screw inside it and sprayed carb cleaner into it, and put it back together.  However, now the saw won't run at all unless I spray a shot of carb cleaner into the carb and it dies once that's used up.  Even if the vent were plugged it should still at least start and idle for a bit, and there is no vacuum in the tank when I open the cap.  So I'm actually regressing instead of progressing.  It's going into the shop tomorrow.  I'm sure I could fix it eventually but I'm too annoyed at this point and don't want to mess with it any longer.  Plus the guy I bought it from who said it was a good running saw said he'd pay me back for the repairs.


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## kevin j (Oct 2, 2008)

post what you find out please.


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## Joey Jones (Oct 3, 2008)

Thats why they call it a stihl , because it is still hard to start....I got a Home Depot Echo 49CC with a 20" bar and that thing seems indestructible.... My ex wife did throw it into our swimming pool during one of her rants...Luckily she is gone, but the saw lives ....I took it apart after the pool incident and dryed it out and with a little squirt here and there and it started on the first pull. She got the Webber Grill though


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## eba1225 (Oct 8, 2008)

Well I removed my muffler and air filter and ran the saw and had the same problem with it bogging down and sometimes dieing on reving it up.  I did notice that there was a spit of fuel coming out of the carb. Have rebuilt the carb. with no change.

It seems to idle well but the high speed is where the problem is.

BTW, the cylinder is perfect.


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## taxidermist (Oct 8, 2008)

Start it and get it warmed up and adjust the H screw while you are at wide open throttle then go back and adjust the L screw to make it idle good. 1 turn out on both is a good starting point but needs adjusting from there.


Rob


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## JRP3 (Oct 28, 2008)

Finally got the saw back from the shop, carb rebuild did the trick, $94 later.  Of course they also replaced my brand new spark plug with another new one and put on a brand new $26.00 air cleaner, which it could have used but wasn't the reason it wouldn't run.  Wasn't too happy with that but after waiting this long I was happy enough to get the saw back that I didn't bother arguing with them too much.  Maybe that's their plan, hang onto the saw for so long you just want it back no matter what  :ahhh: 
The guy who sold it to me agreed to give me $50 towards the repairs so I didn't come out too badly in the end.  Thanks for all the help here.


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## JRP3 (Oct 31, 2008)

Spoke too soon  :-S   Starts and runs great, until I actually try to cut with it, then it bogs down again.  Back to the shop with it.  Probably just needs mixture adjustments but they should have done that after the rebuild so I'll let them mess with it.


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## Dill (Oct 31, 2008)

Hows your fuel filter?


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## billb3 (Oct 31, 2008)

My 2000 026Pro is at the shop for the exact same thing.

Supposedly there's some plastic tube that dries out - controls something in the carb.
PITA to change. Supposedly common with 026 motor. Inexpensive part, the job ends up all labor for dis-assembly / assembly.



Last Spring I thought  I had bad gas - a new mix would run longer.  Last weekend we had a wind storm and a huge oak  snapped came down taking a pine and a hemlock with it in my driveway.
Darn saw wouldn't cut  more than 2 cuts before it just stall and died.
Had to wait to cool off before it would restart, but basicilly won't run more than a minute.


Figures, the one time I need it - right now.
If I cut a lot I'd buy another one.
One to use, one to curse.


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## JRP3 (Oct 31, 2008)

Dill said:
			
		

> Hows your fuel filter?


Brand new.


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## JRP3 (Oct 31, 2008)

billb3 said:
			
		

> My 2000 026Pro is at the shop for the exact same thing.
> 
> Supposedly there's some plastic tube that dries out - controls something in the carb.
> PITA to change. Supposedly common with 026 motor. Inexpensive part, the job ends up all labor for dis-assembly / assembly.


That might be something called an "impulse tube" and I assumed they would have checked that when they rebuilt the carb, but maybe they didn't.


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## billb3 (Nov 3, 2008)

JRP3 said:
			
		

> billb3 said:
> 
> 
> 
> ...



Impulse tube may have been what he was suspicious of. 

The carb hadn't been rebuilt. I brought it in because I couldn't get it to stay running. In fact this 026Pro hasn't been touched or back to the shop since new in 2000.
Ended up being a split hose barb (nipple) white plastic. Took the guy a whie to find it, kept failing a pressure test. Rather than replace the carb he reamed out  where this 2 part nipple went into the carb body and replaced with an older style from an old carb.
Runs like new.
I hope $63 with a quart of bar oil was a decent deal.
He kept remining me the gallon jugs were "over there". I didn't get the hint until I got this one empty.  
Figures my saw would act up when a huge oak falls in the driveway.
If I cut enough wood I'd have a second saw.


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## JRP3 (Nov 3, 2008)

I do as much cutting as possible with my Makita UC 4000 electric chainsaw.  It's quieter, no cloud of smoke around me, and cuts reasonably fast through most logs.  Most of the stuff I deal with is 12 inches or less though I have cut 20 inch red oak with it.  If I can get the log within the range of a 100 ft extension cord I usually use the electric.


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## bsruther (Nov 4, 2008)

That screen inside the muffler is the spark arrestor. If it's clogged with carbon it can adversly affect the saws performance. Clean it, even if it looks clean. I had the same problem with my old saw. Cleaned the spark arrestor and it ran like new.
What can it hurt?


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## JRP3 (Nov 17, 2008)

Got the saw back, runs great!  Finally.  The guy asked me if I had put gas in it because it smelled stale, I said the only gas in it was what he put in after he rebuilt it a few days ago, then he said the carb was way out of adjustment and he said he was sure he adjusted it after the rebuild.  I said maybe the guy who took it in at the shop messed with it trying to fix it.  He also put a new plug in it, (the third one since I put one in when I tried to get it running and he put one in when he first rebuilt it).  Either way it runs fine now and he didn't charge me any more so I'm reasonably happy.  My first real saw  :cheese:


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