Oklahoma,AR,MO,KS,TX GTG (Next GTG 08/27/2016 ) Fort Scott, KS

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Spring cleaning in the garden shed.

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Sent from my SM-N910V
Hey fellows, that homelite gas can is SO COOL!!!
I HATE new style gas cans!!!
You have to be a mechanical engineer and very patient with perfect form to opperate modern cans.
 
Went riding horses with my cousin this morning. Been a LONG time since I've done that, but had a great time. Only bad thing out of the whole thing is that my pelvis feels like it's been beat about 4 inches wider. :surprised3: :)
Ok, now I'm a LOT sore. I've got an idea. I have an old saddle. What if I combined the saddle with the front seat of a Ford Bronco 2. Should be more comfortable, plus it would have seat belts. :surprised3:
 
Would someone mind making me smarter on vacuum testing, please? Will a saw hold a perfect vacuum, or will it eventually level out with the atmosphere? The saw that I'm fooling with leaks down from 10 inHg to zero in about 9.5 minutes. Assuming on my part that it will not hold a perfect vacuum, what is the acceptable rate of leak down?

Thanks.
 
Would someone mind making me smarter on vacuum testing, please? Will a saw hold a perfect vacuum, or will it eventually level out with the atmosphere? The saw that I'm fooling with leaks down from 10 inHg to zero in about 9.5 minutes. Assuming on my part that it will not hold a perfect vacuum, what is the acceptable rate of leak down?

Thanks.

Sent from my SM-N910V
 
I'm not an expert, but your vacuum drop sounds ok to me.

Almost nothing holds a vacuum forever. It seems to me that you should have a better measure of what it drops to in just one minute. What really counts is the rate of vacuum failure. Sadly, I am not able to answer the acceptable leak-down rate.

I have always used a different method: how much vacuum we can pump onto the gauge using our little pump-up vacuum gauge. 5lbs is about good for us. After that, it all bleeds back off.

You really should do both a pressure test and a vacuum test: they are not the same thing. I have seen saws that passed a pressure test, yet failed the vacuum, and vice-versa. Use the pressure test when you want to see where the vacuum test is failing: pump it up, then sink the whole block into a big pot of water. Trace the air bubbles!

A while back, some fine fellow put up this file at ArboristSite, which I saved. Click link for a rather definitive procedure: https://www.dropbox.com/s/uol69qbzfjb1541/Vacuum checking a chainsaw.pdf?dl=0
 
Doubting my memory, it turns out that 4.91 lbs of vacuum is equal to 10" of mercury.

Also: leakage can occur from almost any part of the saw, not just the seals or the decomp valve. Almost the most important leak to find is any crankcase leak, anywhere on the seam between the two halves (depending on the saw you are working on). Cylinder gasket, spark plug, crankcase vent, even the manifold seals that you use to do the test can leak. It seems to me that somewhere in my distant past I even had a cylinder with a pinhole leak right through the casting.

Use the pressure test to find your leaks.
 
Good info. I don't currently have a way of applying pressure, but it looks like I need one. The saw is back together enough that I was able to start it. Idles up and down and back again.....revs really high when it's flipped upside down. Something appears to still be sucking air from somewhere.

I should've ordered oil seals when I had it apart, but didn't. Lesson learned. Hopefully it's not leaking at the case halves. Ahh well, at least it's clean now since it looks like I need to tear it back down. Also need to locate a non-snorkel top for the carb before it gets finished.
 

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