Causes of Saw Failure

[ReggieT]

Darwinism is a pretty good saw killer.

Darwin Award Winner!

 

[Yoopermike]

Darwin Award Winner!
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Well, no not really. Technically speaking, it looks like that saw is still alive and well. The truck... not so much.

 

[Boomer 87]

OMG

 

[SteveSr]

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.

Not necessarily... Two strokes require *more* fuel to make power at a lower RPM under load. The main thing is that the 4-stroke goes away when under load.

Found this out with a weedeater with a string head (under load). Set the carb high screw to maximum RPM (power) with the normal string length. Then lengthened the string slightly which increased the load and lowered the RPM. I then found that I had to richen the HS screw to to get the maximum RPM (power) with the new, longer, string length. A saw should work the same way but it is not easy to measure.

 

[ReggieT]

Well, no not really. Technically speaking, it looks like that saw is still alive and well. The truck... not so much.

Probably has cut his hoof off by now...if the Einstein pictured had his druthers and the IQ of a ham he'd probably swap the POS saw for P/U truck wholeness...lol

 

[Full Chisel]

Heat is the killer of 2 strokes...lean tune, dirty saw, dull chain, etc.

 

[svk]

Bad crank seals, bad tune, bad gas, poor oil/not enough oil, air filtration failure, overheating from using dull chain, intake air leak, base gasket failure, too hot of spark plug.

 

[merc_man]

Darwin Award Winner!
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Whats he doing to that poor peace of wood?

 

[merc_man]

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.

if you just add more oil it will accually run leaner? I would have thaught richer.

Not trying to sound like smart @$$. I didnt know that you would have to tune it richer.

 

[Full Chisel]

if you just add more oil it will accually run leaner? I would have thaught richer.

Not trying to sound like smart @$$. I didnt know that you would have to tune it richer.

More oil = less fuel. A richer oil mix actually runs slightly hotter due to reduced evaporational cooling from the incoming fuel charge. But the tradeoff is more residual oil coating for the bearings and metal to metal, frictional surfaces.

 

[ReggieT]

Whats he doing to that poor peace of wood?

Hmm...that is kinda queer looking...perhaps he also has a "wood fetish" or something!

 

[Okie]

I've recently started using a infrared thermometer to test the jug temp of gas operated chain saws while into a heavy cut.
Real easy to use and will immediately tell you if the saws jug (piston and cylinder area) is overheating BEFORE it goes into self destruction.
You will really be surprised at how fast (rapidly) a chainsaw engine's jug temperature will overheat when it starts running lean and into a heavy cut, even though the rpms are not being exceeded.

 

[blades]

Never thought about trying that.

 

[ken morgan]

I've recently started using a infrared thermometer to test the jug temp of gas operated chain saws while into a heavy cut.
Real easy to use and will immediately tell you if the saws jug (piston and cylinder area) is overheating BEFORE it goes into self destruction.
You will really be surprised at how fast (rapidly) a chainsaw engine's jug temperature will overheat when it starts running lean and into a heavy cut, even though the rpms are not being exceeded.

what cylinder temps are you seeing? and where are you measuring at the exhaust side of the cylinder or the intake side etc. The reason I ask was I was thinking up a way to datalog using a wideband, wired tach and an egt gauge....but I am not sure what the optimal values should be for a 2 stroke.

 

[leeha]

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.

Assuming you bought a new saw. Just do what your dealer recommends as the
saw is still under warranty. Let them tune it and read your owners manual.
Keep your chain sharp at all times. Without a sharp chain your saw is worthless.


Lee

 

[naturelover]

Darwin Award Winner!
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Well, at least he doesn't have far to go to load it...


Sent from my iPhone 6 using Tapatalk

 

[Conquistador3]

I'll add to the list losing your saw from the back of your truck while at highway speeds.

 

[CR888]

Straight gassing is not an issue 'you' have to deal with. For the years I've been an AS member not once has an op said 'he' straight gassed a saw. Its always the neighbour, distant uncle, odd guy who gave me this saw etc. So it's always someone else and YOU never have to worry about the issue.

 

[svk]

Straight gassing is not an issue 'you' have to deal with. For the years I've been an AS member not once has an op said 'he' straight gassed a saw. Its always the neighbour, distant uncle, odd guy who gave me this saw etc. So it's always someone else and YOU never have to worry about the issue.

Hasn't happened to me, yet (knock on wood) but it could still easily happen. You are mixing gas and someone calls or stops by, you grab the wrong can, etc.

I'm sure more than a few AS members have done this but won't own up.

 

[a. palmer jr.]

Running the wrong kind of oil can kill a 2 stroke. What Boomer is talking about carbon can pretty well be eliminated by using Klotz Techniplate oil. I used to use it in motocross bikes and it never produced any carbon. If you mix it too rich it just comes out the exhaust as a liquid and a mist. BTW, I'm not involved with the Klotz company in any way, just an experienced user. I'm on a budget now and don't use it because of the cost but it is an engine saver..