Causes of Saw Failure

[Steph79]

I'm hoping to benefit from the experience of others and learn what the typical causes of saw failure are? I thought of this after reading a thread where somebody mentioned that they scored the piston and destroyed a saw after trying to cut through a difficult stump. It surprised me a little, I just assumed that as long as he was using the right fuel / oil mix that the saw could do it with enough time or worst case he maybe would burn out the chain and not get the job done.

I'm new to saws and just purchased my first good one, this has me a little concerned that I might be doing something stupid and wrecking my saw without realizing it. I do use 91 octane, ethanol free gas and run the saw dry after every use, are there other precautions that people take? Maybe letting the saw rest if its working hard or if its really hot out?

Any pointers would be appreciated.

 

[HarleyT]

Lean seizure. Where the piston gets so hot, that it starts melting, and pins the rings down.

 

[HarleyT]

You can lean-seize a saw by adjusting the carb wrong. The leaner the air-fuel mix, the faster the saw goes...
To a point...
And as it goes faster, it gets hotter of course. But the heat goes way up, because also with that heat, there is less lubrication, because the lube is in the gas/mix, and there is less of it.

 

[HarleyT]

Also can be leaned out by fuel line leaks, carb clogs, seal crankcase leaks, etc.
Bad fuel has killed many as well.
And of course, no lube in the fuel can do it as well.

 

[merc_man]

Its nice yo have two saws in the heat. I run a tank through one then let it cool while using the other. Best thing is use a good sharp chain. Little heavy on the oil if its real hot. Could even mix it 32:1. I usually mix 40:1. Others may think different but that works for me.
Keep saw clean, blow out air cooling fins on cylinder and blow out around flywheel area. Keep air filter clean.

 

[HarleyT]

Best advice, is when/if your saw starts acting squirrelly. Shut it down, and find out why.
Don't keep trying to run it.
Also, don't just grab a screwdriver and try to adjust it out, that is no fix, it is just trying to compensate for a problem.

 

[Steph79]

I've been trying to do some easy cuts after a couple of bigger ones to let the saw cool off a little, 2 to 4 hrs is the longest amount of time I'll spend cutting at one time generally. Just wanted to make sure I wasn't doing something stupid without realizing it.

 

[HarleyT]

What saw did you get?

 

[Steph79]

Makita EA6100. Great saw so far, don't have a lot to compare it to though.

 

[HarleyT]

Looks nice!

 

[GeorgiaVol]

Loaning a saw out will kill one pretty quick too.

 

[blades]

thats a nice air filter on that one. note most saws are coming from oem running on the lean side to make epa specs- one of the reasons for a new saw piston meltdown - course when you go back to the dealer with it - 99% of the time they will tell you wrong fuel mix or something along those lines. Somewhere I read running a fat oil mix ie 40:1 vs 50:1 can be just as bad. Unless the unit is re-tuned.

 

[Steph79]

The shop I bought this one from fueled it up and adjusted the carb before I left so it should all be set properly I hope.

 

[SteveSr]

Its nice yo have two saws in the heat. I run a tank through one then let it cool while using the other. Best thing is use a good sharp chain. Little heavy on the oil if its real hot. Could even mix it 32:1. I usually mix 40:1. Others may think different but that works for me.
Keep saw clean, blow out air cooling fins on cylinder and blow out around flywheel area. Keep air filter clean.

Watch out if you change oil ratios as the carb sets the (fuel+oil)/air ratio so if you just add more oil you are actually leaning out the mixture! If you do this then check and retune as necessary.

 

[Big_Wood]

i know lean tuning can do a saw in especially in extreme duty situations like milling but the number one killer of 2 strokes IMO is bad gas. i've ran them pretty dang lean and had them survive just fine. no 4 stroking at all. not telling anyone to try that at home though lol.

 

[Jonny Quest]

Straight-gassing any 2-cycle engine is the quickest way to kill it...

JQ

 

[GeorgiaVol]

Along with dropping them from trees or running them over with your truck.

 

[Boomer 87]

I tune mine on the fat side, I don't mind having to change a plug now and then even though I haven't had to yet. I would like to get into tuning with a digital tach though bc i may be leaving some power on the table.

 

[Yoopermike]

Darwinism is a pretty good saw killer.

 

[Boomer 87]

Carbon buildup on top of the piston. Can be bad from improper tuning poor fuel and what not. carbon chunk can come off and score the cylinder pretty good