Stihl 029 - Starts but won't idle

[OhSnap]

New to the site, first time posting, fairly novice as far as working on chainsaws, but I like to think I'm pretty mechanically inclined and a fast learner.

I picked up an 029 in pretty rough shape and I've been trying to make it better.

The problems:
- Hole burned in the bar/chain oil tank, top side under the muffler, patched it up with JBWeld.
- Muffler bolt tube busted, extracted it through a hole in the muffler and then patched with JBWeld. Would have welded it up, but welder was out on loan that day. So, the muffler is a bit opened up.
- Piston and cylinder have some scoring on the muffler side, seems light to me.

The saw will start and run at full throttle, but it won't idle. Don't know how long it would keep going at full throttle, I never pushed it very hard. I have rebuilt the carburetor (my first time).

My main question is, is the piston/cylinder scoring the likely cause of it not idling? If so, is there anything for me to do (besides replace them)?

 

[Gypo Logger]

The first thing I'd do is turn in the idle screw (LA) at least one full turn, start saw and then turn in or out the low speed screw to get the fastest rpm, then back out L 1/4 turn, then back off Idle speed screw (LA) till chain stops turning.
You may want to find out why the piston is scored though.

 

[OhSnap]

I should have mentioned... I attempted to tune the carb after the rebuild, but no luck getting it to idle that way.

The first thing I'd do is turn in the idle screw (LA) at least one full turn, start saw and then turn in or out the low speed screw to get the fastest rpm, then back out L 1/4 turn, then back off Idle speed screw (LA) till chain stops turning.
You may want to find out why the piston is scored though.

 

[OhSnap]

I also check the lines for leaks, nothing there either.

 

[HarleyT]

Look at the fuel line again closely for cracks, between the tank and carb, bend the line, cracking is a common problem on this model....

 

[OhSnap]

I took the fuel line off and used an air compressor to make sure it had no leaks at all.

 

[gitfiddle]

[QU

I took the fuel line off and used an air compressor to make sure it had no leaks at all.

I would also do a PSI check for a possible cracked cylinder or bad oil seals.Had the same problem with my MS 290 and the cylinder was cracked.
OTE="OhSnap, post: 6212261, member: 149753"]I should have mentioned... I attempted to tune the carb after the rebuild, but no luck getting it to idle that way.[/QUOTE]

 

[OhSnap]

I would also do a PSI check for a possible cracked cylinder or bad oil seals.Had the same problem with my MS 290 and the cylinder was cracked.

Interesting, hadn't thought of that. Compression test the only way to tell or could I spot it if I look close enough? The saw is currently fully disassembled, and I don't want to buy the parts needed to reassemble if it needs a new piston and cylinder.

 

[HarleyT]

Sounds like you need a new piston, put up some pics.

 

[OhSnap]

Pics of the piston and cylinder scoring.

 

[HarleyT]

I wouldn't waste time on it myself. Replacing the piston/rings at a minimum, then fix the problem that caused it.

 

[HarleyT]

The cylinder will buff out fine, what diameter piston is it?

 

[OhSnap]

I assume the previous owner ran it too lean or something like that, and it got too hot. As far as not being worth the time, that's kind of what I figured. I didn't figure it was worth salvaging at this point. I'll try to get back what I put in by selling off the remaining good parts. Shouldn't be hard since my investment is $30 and it came with a bar and chain.