The Forestry Forum

Well, my first post here and with the couple minutes poking around it looks like I'm going to have hours of great reading material here. I'll just cut to the chase though. 

I recently picked up an older 034AV Stihl to fill the gap in my line up between my 291C-BE and my 660 mag. Got it for a song at $40, was told it was hard to start and won't stay running, bogs and dies. I hoped it was a plugged carb or spark arrestor screen. Something cheap and easy. Well would not appear the case. 

How bad does this piston look? (Having trouble uploading the picture, will edit the post shortly) 

When I pull it over slow with the muffler off, I can see the gas squish by the sides of the piston and bubble up a bit. It feels like the saw has 1/2 decent compression. Anyone able to tell me what it should be at?

Welcome aboard, glad to have you with us. A healthy saw should have at least 125psi compression. A quick way to check is by holding the saw by the starter handle, if it drops it needs freshening up.
Before tearing into it you shold have the crankcase pressure/vacuum tested. A problem with seals or gaskets leaking will show up, no point replacing the top end only to have another failure. For help posting pictures scroll to the bottom of the home page for a tutorial. Good luck and keep us posted.