I had this saw for about 4 years and in the beginning of this year I was using it to cut some trees and it shuts off after using it for almost the whole day. There was still gas and oil in it when it died, so I left it and the next day I tried starting it but it'll start then boggles down and died. I cleaned the old carburetor, then adjust the carb, and tried starting it and again it'll start but boggles and died, but it'll stay on as long as i hold the trigger, but as soon as i left off the trigger the pole saw just dies. Next, I replaced the carburetor, spark plug, but it does the same, boggles and die, then i replaced the ignition coil, fuel lines, and fuel filter, but even then it didn't work. I also notice that if i come the next day the gas in the primer bulb is gone and when I remove the cover I can see gas leaks, but this was before i replace the fuel lines. So what's causing it to not start or stay running since i replaced most parts? I also made sure that every parts are tighten and I also forgot to mention that the spark arrestor screen was removed, but the pole saw still don't work.
remove the muffler and see if it works fine
As you had been using it all day chances are carbon has built up on the spark arrestor screen & is choking the engine
Carbon can also build up in the exhaust port on the cylinder which also chokes the engine because the exhaust can't get out .
This happens vary quickly if you run a mix with too much oil in it .
Remember what the muffler is for
They are VERY loud without it and the noise pulses can be painful.
while the muffler is off have a peep inside the cylinder ( as if you wouldn't ) and look for scoring of the bore and in particular for damage to the rings
When i was taking out the carburetor i had already peeked in to look at the cylinder and ring on both sides and both looks fine (cylinder has normal scratches). Today, i tried starting the saw without the muffler, but it starts then dies.
#8
StarTech
Have you even bother to tune the carburetor? New Stihl carburetors are only tuned to will start condition.
When I get into these situations I instal a spark tester or Colour Tune
Clamp the saw by the bar making sure it can not move ( some times I also support the engine end with a stand
Then it is a case of starting the saw & watching the spark tester
Some times I even video it so I can play back at a slower speed
I am looking to see if it stops sparking then stops spinning or sparks all the way to shutdown
If the former then the coil & wiring is suspect
so the next step is to unplug the coil at the coil to see if it is the coil or the wiring/switch .
If the latter then I know it is a fuel problem
#12
StarTech
It also can a compression problem. I just ran into a similar problem with an old FS40. You could start it and run it holding the throttle open (labored at full) but as soon you let up to idle it would die. Further tests indicated it compression had dropped to 90 psi which is what I have found over the years to be too low as most 2 cycle units here requires 100+ psi to idle right.
