stihl 026

[aerow27]

I have had this saw for about 8 years.
it's a 026 pro
runs good, 20" bar .325 chain
just upgraded to a 194 carb after my muffler mod
saw gas really good throttle response, seems to pull the 20" chain well

I bought a compression test to test one of my other saws.
so I decided to test this 026 also. said 100 psi?
seems low for how well it runs
piston is in good shape, no scoring
is it just getting wore out and needs new rings?
with the bar on, you can hold the recoil and the saw will not drop down at all. I was told that as easy way to check compression without a tester

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[TLG]

Crude but effective test. With 100 psi compression that saw would drift downward while in suspension. I suspect you may have a leaking hose crimp, check valve, etc. Did you pull it 3-5 times and did the gauge quit moving??

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[aerow27]

I pulled it 5 or 6 times
I was thinking maybe the decomp valve could be faulty also
not like that saw needs one, maybe I should plug it?
I'm going to try it again tomorrow to see if I get the same results
maybe soapy water on fittings to check for leaks in the hose and decomp valve?

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[TLG]

Yes on all the above. Also spray the plug hole and comp tester hose, valve, etc. while cranking. If it's leaking she will be a bubble blower!!

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[Mad Professor]

It might not be the correct type of compression gauge for a chainsaw/small engine.

 

[aerow27]

what type would I need?
didn't know there was different kinds?

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[aerow27]

this is what I have
said comes with adaptors for small engines
fits my plug hole?
0-300 psi

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[pioneerguy600]

this is what I have
said comes with adaptors for small engines
fits my plug hole?
0-300 psi

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That set will give very low readings on a chainsaw cylinder, any compression gauge used for small engines must have the Schrader valve in the part that screws into the sparkplug hole to get an accurate reading. The Schrader valve must also be of the type used for small engines like saws, not the common ones used for automotive engines. Tons of threads on that subject on this forum.

 

[farmer steve]

@aerow27. What he said.

 

[aerow27]

well, I guess I need to try to find the right kind of tester
thanks guys

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[farmer steve]

Do a search for CT. Plenty of threads on what guys use here.

 

[aerow27]

my tester seems to have a valve of some sort on this end of the hose. it's on the inside and I have no way to get to it. I can feel it move back and forth if I blow into the hose
if that what you mean by having the Schrader valve on the plug end?

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[pioneerguy600]

It needs to be at the very tip, actually the release pin projects out a bit past the brass screw in adapter and it will need a soft, ( white band) Schrader valve swapped in, most come with a red band automotive Schrader and they are too stiff for small engine work. If an adapter is required to be screwed onto the hose end to fit the sparkplug thread in the cylinder then that will also provide a false lower reading on the gauge.

 

[Agent smith]

Mac tools makes a nice compression tester set. That's what I use and has the schrader valve right at the tips of the adapters. I don't know how often you'll be using the tester but if its often then its worth the $179 new. Theres used ones on ebay too if you wanted to save a few bucks

 

[pioneerguy600]

I don`t own this but have read on several threads that the OTC 5604 small engine comp tester set is a good one and not crazy expensive.My own sets are older good quality gear that has lasted me a lifetime, Tuffy, Hastings and Snap ON.

 

[drf255]

If it runs well and the piston looks good, stop worrying.

 

[aerow27]

I wouldn't say I'm worried
just wanting to be able to test and diagnose my saws

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