SteveSr
Addicted to ArboristSite
Hello,
I have been fighting a weird issue with an old (pre-EPA) 025 (1123 series) saw. This was a homeowner saw that looks like it sat for years. The piston looks like a new saw. It tunes up and runs fine after a short warm-up. After a couple of buried bar cuts in 12-14" logs it starts to run noticeably leaner at WOT so I adjust the H screw a little bit. The idle speed also increases slightly so I back off on the LA adjustment. After the saw is completely heat soaked and warmed up the saw starts running noticeably rich at WOT and the idle speed drops to where it wants to stall.
Been through the carb twice and found a few issues but hasn't altered the above behavior. The impulse line has been replaced. Finally suspecting a weird air leak I removed the muffler and carb and installed blocking plates. Yes, I found a very slight air leak as follows:
Pressure 10 -> 5 PSI in 1:09 minutes
Vacuum 10 -> 5 in Hg in 0:35 minutes
Immediately suspecting the crank seals I hit it with some Windex on both seals and saw no bubbles under pressure. Today I came back with a Q-tip and soapy water. The water happened to flow past the seals and along the case seam and voila! there were bubbles on BOTH sides of the seam near the junction with the crank seal.
So it looks like I found the culpret! Stihl used some sort of white colored sealant which apparently has failed. So it looks like it is time for a complete teardown and new seals. Can anyone offer any tips to make this job easier and if I should use the red Dirko sealer or if you have found something better.
Thanks,
Steve
I have been fighting a weird issue with an old (pre-EPA) 025 (1123 series) saw. This was a homeowner saw that looks like it sat for years. The piston looks like a new saw. It tunes up and runs fine after a short warm-up. After a couple of buried bar cuts in 12-14" logs it starts to run noticeably leaner at WOT so I adjust the H screw a little bit. The idle speed also increases slightly so I back off on the LA adjustment. After the saw is completely heat soaked and warmed up the saw starts running noticeably rich at WOT and the idle speed drops to where it wants to stall.
Been through the carb twice and found a few issues but hasn't altered the above behavior. The impulse line has been replaced. Finally suspecting a weird air leak I removed the muffler and carb and installed blocking plates. Yes, I found a very slight air leak as follows:
Pressure 10 -> 5 PSI in 1:09 minutes
Vacuum 10 -> 5 in Hg in 0:35 minutes
Immediately suspecting the crank seals I hit it with some Windex on both seals and saw no bubbles under pressure. Today I came back with a Q-tip and soapy water. The water happened to flow past the seals and along the case seam and voila! there were bubbles on BOTH sides of the seam near the junction with the crank seal.
So it looks like I found the culpret! Stihl used some sort of white colored sealant which apparently has failed. So it looks like it is time for a complete teardown and new seals. Can anyone offer any tips to make this job easier and if I should use the red Dirko sealer or if you have found something better.
Thanks,
Steve