Rate my pressure/vacuum test results

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OneStaple

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This is a crankcase vacuum and pressure test on a Stihl 026. The service manual says it should hold vacuum/pressure (0.5 bar of each) for 20 seconds. From what I’ve read on here, it seems like people do something as short as that to up to 20 minutes. Not sure what the “right” answer is, so I thought I’d just post results and see what you think.

Pressure: Pumped to 7.5 psi. After 10 minutes, it was at 6 psi. Seems not horrible but not great.

Vacuum: Pulled 15 inHg of vacuum. After 11 minutes, it was at 13 inHg. Then I turned the crank about five times and it dropped to 12 inHg, although I think I bumped the seal on the inlet port a little in the process. An additional 11 minutes (22 total), and it was at 10 inHg.

So, this obviously passes the test in the manual, but still doesn’t seem perfect. Is this good enough? Change seals now just because, or run the saw longer until there’s actually a problem? I’m sure opinions will likely be all over the map on this.

Thanks,
Tyler
 
This is a crankcase vacuum and pressure test on a Stihl 026. The service manual says it should hold vacuum/pressure (0.5 bar of each) for 20 seconds. From what I’ve read on here, it seems like people do something as short as that to up to 20 minutes. Not sure what the “right” answer is, so I thought I’d just post results and see what you think.

Pressure: Pumped to 7.5 psi. After 10 minutes, it was at 6 psi. Seems not horrible but not great.

Vacuum: Pulled 15 inHg of vacuum. After 11 minutes, it was at 13 inHg. Then I turned the crank about five times and it dropped to 12 inHg, although I think I bumped the seal on the inlet port a little in the process. An additional 11 minutes (22 total), and it was at 10 inHg.

So, this obviously passes the test in the manual, but still doesn’t seem perfect. Is this good enough? Change seals now just because, or run the saw longer until there’s actually a problem? I’m sure opinions will likely be all over the map on this.

Thanks,
Tyler
Dont assume the seals are leaking ,the leak could be ffrom other places, spray soapy water on the seals the plug, base of cyl etc and see what you find. No luck that way ,dunk it in water .
 

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