I just got a new Husqvarna 550xp and tested the compression and it only came out to 90psi. So I tested the compression on my well broken in 562xp and it reads 105psi. I also have a Chinese Redmax clone that I got for fun and it reads even higher at 115psi. I always thought that 150psi was considered the "A" grade so why are mine so low? And is it normal for these pro grade Husky's to have lower compression?
Compression
- Thread starter sambruin7
- Start date
Help Support Arborist Forum:
Spectre468
ArboristSiteNoob
Shoulda bought you a Stihl...
Chainsaw Jim
CJ Saws, LLC
I think your compression tester is toast or you're not pulling them enough times.
You need to keep pulling until the needle stops climbing if the tester is good.
You need to keep pulling until the needle stops climbing if the tester is good.
Even if my tester is reading low, it's consistent and shows that my Husky's are lower than even a Chinese Redmax. And yes, I know how to use a tester, I pulled at least 6 times until the needle wouldn't go up further.
What tester are you using?
Is this the first time using it?
The spark plug hole adapters I'm using are from Harbor Freight. I just noticed that the smaller adapter's for the Husky's don't seem to be sealing as tight as the larger adapter required for the Chinese Redmax. So my test was inconsistent and unreliable. I really need to get a better tester or new adapters. And btw, the Husky 562 is running awesome and the 550xp is still being broken in.
Had to be something like that!
Big_Wood
westcoast dweller
you have nothing to worry about. just go cut wood. i have an adapter for the 10mm plug but the results turn out so low it's not even worth it. the adapters add volume to the combustion chamber. only way to get an accurate reading is if your schraeder valve is right in the threaded tip of the tester. i wish i could find some adapters with threads for a schraeder valve.
ashy larry
ArboristSite Operative
Good info, i was wondering why my Harbor Freight automotive tester never gave me a compression reading...ever. If i pull it enough will it work or do i need to cut the hose off and start over?
Chainsaw Jim
CJ Saws, LLC
The auto parts stores like Knecht's have decent testers for the same price as harbor frail. You may not get the 10mm adaptor though.
arrow13
ArboristSite Operative
I just ordered both sizes of spark plug hole adapters to test old and new Husky's for crankcase pressure and vacuum. Found them at a saw shop in southern Oregon along I-5 in M. Creek. They're in the mail as I type along with the rubber wedges for blocking off intake and exhaust. I use a Matco compression tester that has a 10mm adapter. Found it on Fleabay.
What tester is it?
I dont even use a comp tester anymore , its either strong or weak to me.
Most saws won't run worth sh!t with those #'s, if your saws run and idle without searching for an adjustment, your gauge is crap. Try another gauge and make sure the Schrader valve is at the tip where the gauge screws into the cylinder. If the valve is not there you will not get proper readings.
Don't use any adapter with a compression tester, they leak and read low. I found that out by experience about 10 years ago.
bikemike
loud pipes save lives
Have you ran the saw before the test or was it never run before testing?
I would venture a guess that your gauge is off by 25 to 30 #'s.
