chainsaw issues. diagnostic?

[e9999]

this time my Echo CS341 arborist saw. Love that little thing. So handy.

Started out a few days ago, I was doing light trimming and when I was using the saw overhead it was sometimes stumbling. First hint?

Yesterday, I was cutting some pine. No obvious overhead issue noticed this time. At first it was OK then it gave me progressively more trouble. When I was revving it out of the wood it sounded fine and was going fast. But then when cutting it would slow down dramatically and feel like it wasn't cutting, no power and little wood chips. If I took it out it ran fast again. To finish the cut (8" across) I had to remove it from the wood, rev it up, and put it back in. Maybe took 5 or 6 times. Felt like lack of fuel or bad carb setting. But then I noticed something odd, the chain was showing a bit of smoke -or maybe it was the guide bar, not sure. Only wisps but not done that before. Seems like something was overheating. At that point, I stopped to figure it out. Had run a file through the chain just before and only cut for about 1/2 hour, just soft fresh pine, and feels sharp still so not a sharpness issue I think. Oil level has decreased -I think- as expected so should have been lube.

First guess is dirt in the fuel system, maybe dirty air filter. Puzzled by smoke.

Suggestions as to likely causes before I look seriously into this?

 

[D'Animal]

Sounds like it was running lean.

How is the compression?

Pull the muffler and look at the pistion.

The temperature of the saw chain will be greatly determine by what bar and chain lubricant you use.

These should be are two completely unrelated issues.

 

[fj40charles]

Should have bought a Stihl.

 

[e9999]

Sounds like it was running lean.

How is the compression?

Pull the muffler and look at the pistion.

The temperature of the saw chain will be greatly determine by what bar and chain lubricant you use.

These should be are two completely unrelated issues.

thanks

gave it a look

compression is 130 psi (when stabilized at max after about 8 pulls)

muffler looks unclogged, exhaust port free of obstructions
top of piston pretty clean, just light deposit, no heavy crud, very clean rings
no major scoring of cylinder walls seen, just couple of light stripes, and plenty of cross-hatch. Can't see the top of the chamber.

plug is shown below, colors are close to real life on my monitor - tan electrodes, black body, it's an NGK BP M8Y measured at between 25 and 28 thous, doesn't look bad to me.

I was running 50:1 stihl oil in 93 octane, 6 months old mix, FWIW

it starts very easily

air cleaner was pretty dirty, cleaned it up. Suspect that may have been big part of the problem, although I can't imagine that would have caused it to run lean.

Fuel filter looks OK but hard to tell. Blew it clean. Tubing I see looks good and supple.

cleaned up the plug a bit and reset to 26 thous


fired it up again. seems like it's running fine now, but need to try on real wood.

checked carb screws but look generally OK, not that the manual is very helpful (how the heck am I supposed to tell if the rpms are between 11,500 and 12,000? and poor language in there as to what to do. And screws have limiters.) No big smoking, sharp acceleration, sounds fast. didn't mess with it much.

Smoke may have been insufficient lube maybe together with too much down force, turned up the lube a bit (I hope). (I always fill up completely both tanks before starting to see if the oil goes down fast enough, set it up so there is always a bit of oil left when the fuel is gone.) Dan is likely right that this was unrelated to power issue. To be checked again.

May be OK now I hope, but any other thoughts -besides carb cleaning- while I'm in the tinkering mood and before I dirty it up again?

 

[e9999]

well, that did it, seems to be working fine now.

but any thoughts on the plug?



does seem to bog down on largish limbs though. Did a live 10" and it was struggling. Don't know if it's cuz the saw is small or it needs tuning. And when that happened there was a bit of smoke coming from the drivegear area. Maybe the clutch cuz it was slipping/struggling? Picked up the Stihl 025 and that went through fine.

 

['74 UA FJ]

Run the Stihl...

 

[e9999]

different uses. I could also run my Farm Boss but that would be less than optimal for small stuff. If you have never run an arborist saw before, you ought to try one. It was a revelation for me. I kick myself for having run saws that were too big for the job since forever. The pleasure, convenience, and safety of a small nimble saw is something to revel in.

What I don't know and what I have to figure out is whether the limitations of my arborist saw is an abnormal tuning issue or just a normal limitation of a small saw. For now, I'll use it where it shines and I'll accept that it struggles with 8 or 10" cuts.

 

['74 UA FJ]

I don't know what an arborist saw is, but I have a Stihl 009, which is tiny. I hardly ever use it because I mainly fell larger trees and then cut firewood size logs from them...

 

[e9999]

I don't know what an arborist saw is, but I have a Stihl 009, which is tiny. I hardly ever use it because I mainly fell larger trees and then cut firewood size logs from them...

I don't know if that is an accepted designation, sorry. I use the term to refer to a small saw that can be used for one-handed operation while trimming small stuff while up in the tree. I also use it to cut smaller branches if a tree or large limb is on the ground. The 009 looks a bit older but seems to be the same general idea. Whereas the one-handed operation sounds a bit iffy at first, in my experience it is probably safer than to use a 2 handed bigger saw while up there if done judiciously for the smaller stuff, I think. Then again, I'm no pro arborist.