gary-stihl
ArboristSite Lurker
Let me try a better camera...
Stihl 026 sometimes starts super hard and sometimes loses power at WOT
- Thread starter gary-stihl
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gary-stihl
ArboristSite Lurker
gary-stihl
ArboristSite Lurker
Tried my "good" digital camera. All it wants to do is focus on the two carbonated bolts on either side of the exhaust port.
I did, however, notice "machine marks" (I think) running around the piston, e.g, circling it, not going up and down. I could see it with my eyes, but i'll be damned if i can get a good pic of it. took like 10-15 shots with my good camera, nothing great
I did, however, notice "machine marks" (I think) running around the piston, e.g, circling it, not going up and down. I could see it with my eyes, but i'll be damned if i can get a good pic of it. took like 10-15 shots with my good camera, nothing great
gary-stihl
ArboristSite Lurker
Check the cylinder/piston for scoring on exhaust side. I just took my 026 apart over the weekend. This is what I found. I'm hoping that I'll be able to clean the cylinder up, and get by with a new piston kit. 
If your gauge is even half accurate and the pictures you've shown, I doubt there's anything wrong with the top end. Pressure/vsc test, check out all the rubber and fuel lines toss a kit in the carb and go from there.
SteveSr
Addicted to ArboristSite
Some cameras have a way for you to set the focal point of the image. Same with cell phones. On my now ancient Galaxy S8 I just simply touch the screen where I want t he focal point to be.
SteveSr
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Circumferential machining marks are a good sign. They should be least worn directly under the bottom ring.
SteveSr
Addicted to ArboristSite
Does that gauge have a schrader valve in the tip or just a straight pipe?
150psi is acceptable, however, it may be artificially high if the top of the piston and combustion chamber is caked with carbon.
SteveSr
Addicted to ArboristSite
Oops! better find out what caused this before you roach another piston.Check the cylinder/piston for scoring on exhaust side. I just took my 026 apart over the weekend. This is what I found. I'm hoping that I'll be able to clean the cylinder up, and get by with a new piston kit.
If there are really machine marks going around the piston, it should be OK. But the question remains why the issue? Back to fuel supply, vacuum and pressure test. As far as compression, I never use a gauge, as internal condition is THE most important an a 2 stroke. The seal behind the flywheel is very common as is all rubber hoses and intake manifold as stated by many. Also bearing cages are suspect. It is an old saw. Age will be a factor.
The throttle linkage also wears and loses the fast idle. I little bend to make it longer makes a big difference on a cold start.
The throttle linkage also wears and loses the fast idle. I little bend to make it longer makes a big difference on a cold start.
SteveSr
Addicted to ArboristSite
1618 is the filter that you want for the compensating carb. The Ebay listing looks to be genuine. You can also check for the Stihl part numbers and logo molded into the plastics.
It's going to get a rebuild. It will get a top end, crank bearings, and crank seals. All OEM parts of course. I'm just hoping the cylinder isn't rocked, and it just needs a piston/rings.
gary-stihl
ArboristSite Lurker
schrader valve. i put the saw in a vice by the bar, with one hand, held the gauge in tight to the spark plug hole, and the other do several rapid pulls.... and watch the gauge.
gary-stihl
ArboristSite Lurker
Mine does not look ANYTHING like that one! YIKES. Also, looks like you have a crack below the exhaust port or is that just crap that looks like a crack?!It's going to get a rebuild. It will get a top end, crank bearings, and crank seals. All OEM parts of course. I'm just hoping the cylinder isn't rocked, and it just needs a piston/rings.
gary-stihl
ArboristSite Lurker
Yep, aware of that, and I just could not get the iphone 13 mini to cooperate. because the phone is soooo compact, they ditch the micro/closeup lens, as i cannot take anything super close up. Oh well....
gary-stihl
ArboristSite Lurker
yah, i think that is the approach I shall take. Plus fresh 93 oct gas with the Stihl HD oil (next time will get the stuff SteveSr mentioned) and we'll see if she rips or needs more investigation & love
my 036 cuts like crazy; but it too prob needs a tune up
gary-stihl
ArboristSite Lurker
Hey guys. Went to my Stihl dealership and brought in my carb. I have the walbro "WT403B" carb on my 026. I asked the dealer to get me a rebuild kit, he said no such thing from Stihl. I see what appears to be aftermarket ones, like this one: https://www.ebay.com/itm/314010067868 - reasonable to get one of these? if not, what do you suggest?
The Stihl dealer said they'd gladly sell me a new carb for $80.
The Stihl dealer said they'd gladly sell me a new carb for $80.
It should take a k20-wat walbro kit. Just like all the wt series. It's not a stihl item.
gary-stihl
ArboristSite Lurker
ordered. thanks mate.
