Minimal Compression

[Shaunzo]

Lifetime weekend warrior wrestling with a CS-4600 to determine who’s gonna be boss.
What’s minimum compression this saw should still start and run ?
This thing is flooding like crazy and I can’t figure out why. Ty

 

[Fordiesel69]

Diaphragm? I like to see 90 to 100 on a whipped saw.

 

[Chevboy0167]

Yup.... 100 or less is the standard for a more detailed look into the internals or gasket/seal leaks.

I have worked on an old grey body Echo SRM-210 string trimmer that had 81 and it still started and ran decent... power was a bit low of course.

The guy is still running it as far as I know!

 

[Fordiesel69]

Not sure how they do it but those 21. 2 cc beasts will run almost perfect even with a roasted cylinder

 

[telecasterfool]

have you checked the fuel metering valve? remove the fuel inlet hose, plug it, pull the cord until it's clear of fuel. Squirt a tiny amount of fuel in the carb, choke. see if it starts. All of this will tell you if there is enough compression to run, and if you have spark. The rest of the puzzle is getting the fuel system to properly meter under all conditions.

 

[Vintage Engine Repairs]

Anything below 120psi will be a struggle
to start.