026 Leakdown Test

[baddboyy21]

I'm rebuilding another 026. I've replaced the seals. I did a vacuum leak test and it takes two minutes, 50 seconds for the the gauge to go from 10 down to 5. According to the service manual, if it holds vacuum for 20 seconds you are good? I assume my test is acceptable? I could not find an actual leak anywhere.

 

[merc_man]

I wouldnt put any more then 10 psi and should be able to hold that and not loose any. If it does check seal and spark plug for leak ther with soapy water or windex.

 

[merc_man]

Check decomp if its a pro

 

[paragonbuilder]

Did you use assembly oil. If the seals are dry they may leak a little.


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[czar800]

Welcome to OPE! I see your from Pittsburgh!

I would pressurize it to 10 psi and spray her down with soapy water. Don't spray soapy water on it under vacuum.

 

[baddboyy21]

Welcome to OPE! I see your from Pittsburgh!

I would pressurize it to 10 psi and spray her down with soapy water. Don't spray soapy water on it under vacuum.

Yes, near Robinson. I used assembly oil only on the piston and lightly covered the cylinder wall along with wrist pin and bearing along with main bearing.

 

[baddboyy21]

It's a non pro version. Should have added that I also changed the carb boot and the impulse line.

 

[panteliss]

I'm rebuilding another 026. I've replaced the seals. I did a vacuum leak test and it takes two minutes, 50 seconds for the the gauge to go from 10 down to 5. According to the service manual, if it holds vacuum for 20 seconds you are good? I assume my test is acceptable? I could not find an actual leak anywhere.

First check if your pressure-vacuum pump its 100% ok and dont leak , i have stihl oems pump , mityvac and some others and i have find that some of them dont hold after of long time
so the pump leak and you think that the saw leak
Generally if a saw holds pressure or vaccum for 3 -5 minutes we can say that is in very good condition but have in your mind that leaks can apear after the saw will be hot because of expands or from vibrations so if you notice the sound change or something while you working have an open eye if something wrong starting hapend