Will a chainsaw run without the Exhaust/Muffler?

[miller755]

One thing I don't see mentioned, and it may be because it is " an old mechanics tale" because I have never personally had it happen to me, but I have been told, that just because you get spark in open air you won't necessarily get spark under compression if the spark is weak it will be weaker under compression.
I would agree with the others that, if you put in a new dry plug and about a half a thimble full of mix, if you have proper compression, and spark the saw should pop and run shortly

 

[Okie]

You asked about compression testing a chainsaw:
Just keep a heads up when compression testing a small CC engine, you can get misled easily using a expensive Automotive tester reads low on a small cc engine, but ok on a larger cc engine.
Here is couple links where you can review compression testing a chainsaw.
The second link talks about a reasonably priced tester for small cc engines, strandix 1023 at this link. I have never used that gauge.
Here is a link to such.
STRANDIX 1023 COMPRESSION GAUGE FOR SMALL ENGINE SERVICE 3" HOSE 14/18 MM | eBay
Don't be surprised if the compression is somewhat low due to new piston and ring. If really low maybe you installed wrong piston or ring. check compression first dry, then add little bit of oil and re-test. Pull the rope until the gauge quits going up, may take 5 or more pulls. If really low the first 3 pulls and does not go to 80 or over is not a good thing. 125 and up is good enough to usually get a start. 140 and up is good. You also need to review how to pressure/vacuum test a 2 cycle engine block. I suspect you have some type of ignition issue.
Why did the other piston have a CHUNK broken out?
Have you noticed any indication of where a Bubba had been flogging the saw?



http://www.arboristsite.com/community/threads/compression-tester-issues.310133/

(114) Got a new compression gauge and tested a few saws | Arboristsite.com

 

[Yukon Stihl]

No filter on it right now, bran new plug

Try a different plug...

 

[rupedoggy]

CFOD has not been here for over 4 months. I don't think he is listening.