Lakeside53
Stihl Wrenching
It a started back on October 4th with a Post from JD
025 problem adjusted carb, changed filter still runs bad http://www.arboristsite.com/showthread.php?t=25313
Then after much great advice from AS, and the best of intentions, JD has had enough
Fixing to burn it! Stihl 025 http://www.arboristsite.com/showthread.php?t=26417
I figured I could fix the saw quicker than I could type so JD shipped it to me (Florida to Seattle – that’s a lot of Frequent traveler miles for a saw).
It arrrived in Seattle few days ago. Just a typical well worn 025.
One quick peak under the carb box and I could see the impulse hose end staring at me. Way way back in the original thread, the problem was "starts but won't rev up and dies". As many pointed out, the impulse line was one of the likely culprit. It was.
Off with the handle, twist the carb box to the side, and pop back on the hose. Gas it up, pull like crazy, and the starter rope breaks. Mutter ,mutter... New rope, pull again, no go. Pour gas in the carb hole, runs for a few seconds. Hmmm, that carb sure look bright and shiny...
Off with the carb....
Setting : both screws many turns out, not 1 as would be correct. I suspect it was left like that after failure to start in Florida.
Metering side - the metering diaphragm was 180 degrees off, but that's not fatal as the diaphragm is symmetrical around the screws. Diaphragm was correctly mounted on top of the gasket and up the correct way. Metering lever was a hair high, but that's not too bad.
Pump side - hmmm, that's interesting... The gasket was incorrectly against the body of the carb (rotated 180 which means it didn’t fit anyhow!) and the diaphragm was against the cover, so it couldn't pump. Wait, that’s NOT a pump diaphragm - the part used is a Backing Diaphragm with NO pump valve ears (part of the standard WAT kit that's not used on many carbs). NO matter how it was assembled, it would never run.
Dumped the carb into the ultrasonic cleaner (it was pretty clean, but what the heck) for a few minutes, new pump diaphragm and gasket, new metering side gasket (a bit mangled), 1 turn out on each screw, back on saw, 2 pulls and it roared to life. Took it out back and cut a bunch of wood. Nice strong little saw.
Other : The chain wants to run at idle particularly after high speed, so the clutch springs are bad (weak). I’ll drop a set in later in the week. The Recoil side was almost completely blocked with gummy muck restricting the airflow. On these 021-25, 290-310 and 390, it’s real important to keep the cooling path clear. The motor body is very small and can quickly get way too hot if there is no airflow. The saw has 145lb compression so it’s in fine shape. JD – you need to get he correct compression gauge – yours reads 90 as it doesn’t have a Schrader valve in the tip. The air cleaner needs replacing – gummed up with fine particles and it no longer grips the filter box tightly. I’ll try to clean it… The fuel line feels gummy, the impulse hose is hard, but they’ll last a few years more.
Why did the impulse hose come off? At some point in its tender life, the handle was bashed really hard near the bottom right side buffer. This pushed the carb box violently to the left popping off the hose. The handle has a crack on the bottom of the buffer, but still holds the buffer in place. The buffer is distorted and was actually pushed ¾ of the way into the handle mount (for a long time).
So JD, did all this start with some type of impact?
025 problem adjusted carb, changed filter still runs bad http://www.arboristsite.com/showthread.php?t=25313
Then after much great advice from AS, and the best of intentions, JD has had enough
Fixing to burn it! Stihl 025 http://www.arboristsite.com/showthread.php?t=26417
I figured I could fix the saw quicker than I could type so JD shipped it to me (Florida to Seattle – that’s a lot of Frequent traveler miles for a saw).
It arrrived in Seattle few days ago. Just a typical well worn 025.
One quick peak under the carb box and I could see the impulse hose end staring at me. Way way back in the original thread, the problem was "starts but won't rev up and dies". As many pointed out, the impulse line was one of the likely culprit. It was.
Off with the handle, twist the carb box to the side, and pop back on the hose. Gas it up, pull like crazy, and the starter rope breaks. Mutter ,mutter... New rope, pull again, no go. Pour gas in the carb hole, runs for a few seconds. Hmmm, that carb sure look bright and shiny...
Off with the carb....
Setting : both screws many turns out, not 1 as would be correct. I suspect it was left like that after failure to start in Florida.
Metering side - the metering diaphragm was 180 degrees off, but that's not fatal as the diaphragm is symmetrical around the screws. Diaphragm was correctly mounted on top of the gasket and up the correct way. Metering lever was a hair high, but that's not too bad.
Pump side - hmmm, that's interesting... The gasket was incorrectly against the body of the carb (rotated 180 which means it didn’t fit anyhow!) and the diaphragm was against the cover, so it couldn't pump. Wait, that’s NOT a pump diaphragm - the part used is a Backing Diaphragm with NO pump valve ears (part of the standard WAT kit that's not used on many carbs). NO matter how it was assembled, it would never run.
Dumped the carb into the ultrasonic cleaner (it was pretty clean, but what the heck) for a few minutes, new pump diaphragm and gasket, new metering side gasket (a bit mangled), 1 turn out on each screw, back on saw, 2 pulls and it roared to life. Took it out back and cut a bunch of wood. Nice strong little saw.
Other : The chain wants to run at idle particularly after high speed, so the clutch springs are bad (weak). I’ll drop a set in later in the week. The Recoil side was almost completely blocked with gummy muck restricting the airflow. On these 021-25, 290-310 and 390, it’s real important to keep the cooling path clear. The motor body is very small and can quickly get way too hot if there is no airflow. The saw has 145lb compression so it’s in fine shape. JD – you need to get he correct compression gauge – yours reads 90 as it doesn’t have a Schrader valve in the tip. The air cleaner needs replacing – gummed up with fine particles and it no longer grips the filter box tightly. I’ll try to clean it… The fuel line feels gummy, the impulse hose is hard, but they’ll last a few years more.
Why did the impulse hose come off? At some point in its tender life, the handle was bashed really hard near the bottom right side buffer. This pushed the carb box violently to the left popping off the hose. The handle has a crack on the bottom of the buffer, but still holds the buffer in place. The buffer is distorted and was actually pushed ¾ of the way into the handle mount (for a long time).
So JD, did all this start with some type of impact?
