stihl 036 compression

[smitty55]

hey guys great site here. I have a chance to buy an 036 for $400 but its like an hours drive away so i want to make sure i know what to look for.
I know about removing the exhaust and plug to check the piston and cylinder wall. My question is how much if any scoring is acceptable?
Also i'd like to be able to do a compression check seeing as i just bought a tester but my local stihl dealer says he doesnt have that info so I figured this would be the place to ask.
Any help would be greatly apppreciated as i'm supposed to check out this saw tomorrow morning.. tks in advance.


smitty

 

[bigair]

150 psi would be like new. 120 psi low.

 

[Lakeside53]

160+ like new, 145-155 - most of mid life, 130 and below - dying... make sure you have the correct correct tester (schrader valve at the screw in tip) or you'll get a falsely low reading.

Some fine vertical marks on the piston are "o.k." but any "scoring" is not good. Best not to see any marks, and no bright polish (piston) either.

 

[smitty55]

tks for the info guys.schraeder valve..isnt that like on a bicycle or car tire??my tester just has a 14 and 18mm thread size insert so i guess thats no good eh??
btw is $400 a good price. he says its in great shape

 

[TimberPig]

tks for the info guys.schraeder valve..isnt that like on a bicycle or car tire??my tester just has a 14 and 18mm thread size insert so i guess thats no good eh??
btw is $400 a good price. he says its in great shape

You need a Shraeder valve in the end where the threaded insert is for screwing into the plug hole. It will be in the center, to allow pressure to build in the hose to take the hose's volume out of the equation. Small engines don't move as much air as a car engine, so they cannot always give accurate readings without the valve, as you lose significant energy in compressing the air in the hose, thus giving low compression readings.

 

[smitty55]

tks timberpig.not sure i understand. so the valve allows pressure to build up in the hose better, right?
that means i need a special hose cause the one i have certainly doesn't have capabilities for that. guess its made for cars only.

 

[bigbadbob]

tks for the info guys.schraeder valve..isnt that like on a bicycle or car tire??my tester just has a 14 and 18mm thread size insert so i guess thats no good eh??
btw is $400 a good price. he says its in great shape

FWIW I picked up a 034 with a new piston/rings from a saw shop for $285 Canadian cash. Compression is 155psi but it has not had use yet. Got a private deal on a 044 Saturday for $175 it has 165psi.:greenchainsaw: There are deals you have wait and scan the local papers and buy and sell or yard sales.

 

[Lakeside53]

Nice buys!

 

[bigbadbob]

Lakeside can you tell me if rebuilt (rings/piston) saws get any more compression after after a few tanks of fuel or do they pretty much stay the same?? Always wondered.
Sorry to hijack the thread.
bob

 

[Lakeside53]

They will, MAYBE 5-10% up to about 20 tanks or so. Depends on how the bore was honed, or if at all. At the compression you have, I'd just ignore it and cut wood!