ralphbsz
ArboristSite Lurker
- Joined
- Jul 20, 2003
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So we've had a Stihl 026 at home, since 1996. While we are not professionals, we do a lot of amateur tree work (many hours per week), and the 026 has been our main workhorse. About half a year ago, it got very sick, and our son (who is also the 2-stroke mechanic) couldn't get it to run reliably, even with a carb rebuild kit and thorough cleaning. But everything else seemed fine (compression, fuel supply, impulse line, ...). We decided to splurge and just throw a whole new carb into it, only to find that the original Stihl-branded WalBro carb is no longer available at the dealer. The dealer suggested buying the new air filter and cover for the MS260 Pro or 261, because the air supply for the back of the diaphragm comes through a hole in the filter, so the carb doesn't get as dirty. No problem, we get an original Stihl MS260 air filter, the cover from Farmertec, and a MS260 carb from the cheapest mail-order dealer (I think it was $10 with free shipping).
And this is where the story starts to get fun. With the MS260 carb, the saw sort of doesn't want to run. Near impossible to start when cold (have to drip gas into the intake, and then blow compressed air in). Once it runs, it has no reliable idle, so better not take the finger off the throttle. But at least it starts when warm, and otherwise it is nice and powerful. So far, so bad. After half a year of this drama, the saw completely gives out: We can tune it to sort of run at idle speed (not reliably), but the moment you give it gas, it chokes and dies.
We blame the ultra-cheap aftermarket carb, and quickly order a new one from Amazon of all places. Exact same symptoms! No amount of adjusting makes it better. At this point, we come to the (wrong) conclusion that we've had 3 dud carburetors, or else the saw is leaking from the body. Completely take it apart (didn't pull crankcase in half, because everything there looked good), replace base gasket, found absolutely no problem. After 25 years of use without ever replacing rings or piston, it still looked excellent, and has 95 psi of compression. In desperation, we simply put the original Stihl carb back on (it had been deep cleaned in an ultrasonic, and an Oregon rebuild kit put in it). Now the saw runs perfectly and is powerful! My son was laughing, because my only complaint about the saw was that the chain was dull after 2 hours of use yesterday.
I think this means the original problem was simply some dirt somewhere in the carb, which the first cleaning didn't manage to get out.
We're thinking of taking the back plate from one of the cheap MS260 carburetors and still adapt the saw to get its diaphragm air through the hole from inside the new MS260 filter. But first, we'll use it for a few weeks, because it is such a joy to use.
So now someone please riddle me this: The MS260/261 is fundamentally the same saw, with a couple more cc. The Walbro carb used in the 260 is perfectly the same mounting size as the one on the 026 (except for the back plate over the diaphragm). Why would two different Chinese carbs for a 260 refuse to work on an 026? That is very bizarre.
And this is where the story starts to get fun. With the MS260 carb, the saw sort of doesn't want to run. Near impossible to start when cold (have to drip gas into the intake, and then blow compressed air in). Once it runs, it has no reliable idle, so better not take the finger off the throttle. But at least it starts when warm, and otherwise it is nice and powerful. So far, so bad. After half a year of this drama, the saw completely gives out: We can tune it to sort of run at idle speed (not reliably), but the moment you give it gas, it chokes and dies.
We blame the ultra-cheap aftermarket carb, and quickly order a new one from Amazon of all places. Exact same symptoms! No amount of adjusting makes it better. At this point, we come to the (wrong) conclusion that we've had 3 dud carburetors, or else the saw is leaking from the body. Completely take it apart (didn't pull crankcase in half, because everything there looked good), replace base gasket, found absolutely no problem. After 25 years of use without ever replacing rings or piston, it still looked excellent, and has 95 psi of compression. In desperation, we simply put the original Stihl carb back on (it had been deep cleaned in an ultrasonic, and an Oregon rebuild kit put in it). Now the saw runs perfectly and is powerful! My son was laughing, because my only complaint about the saw was that the chain was dull after 2 hours of use yesterday.
I think this means the original problem was simply some dirt somewhere in the carb, which the first cleaning didn't manage to get out.
We're thinking of taking the back plate from one of the cheap MS260 carburetors and still adapt the saw to get its diaphragm air through the hole from inside the new MS260 filter. But first, we'll use it for a few weeks, because it is such a joy to use.
So now someone please riddle me this: The MS260/261 is fundamentally the same saw, with a couple more cc. The Walbro carb used in the 260 is perfectly the same mounting size as the one on the 026 (except for the back plate over the diaphragm). Why would two different Chinese carbs for a 260 refuse to work on an 026? That is very bizarre.
