Damaging Pistons and Cylinders on 660s

[blsnelling]

And if it was an air leak, the operator ignored a lot of tell tale symptoms. A saw with an air leak like that would never idle down properly.

 

[Tree Student]

Well the failure of the 066 was a bad seal on the chain side of the crankcase, my foreman doesn't have as much experience in running saws but is great at keeping my crew productive and getting the job done properly so he's still learning the tell tale signs.

Luckily the local dealer is going to replace everything for me and have the saw back in my hands for under $300, it's a steal if ya ask me but I know he cuts me a great deal because I'm a "commercial" customer.

However I've learned a lot of tips on what everyone here is doing with their gas mixes and I think that was the cause of my 660 chipping the head of the piston on the exhaust port side. So I'm going to mix my fuel a little richer for a while and see what kind of performance I can see.

 

[bcorradi]

Well the failure of the 066 was a bad seal on the chain side of the crankcase, my foreman doesn't have as much experience in running saws but is great at keeping my crew productive and getting the job done properly so he's still learning the tell tale signs.

Luckily the local dealer is going to replace everything for me and have the saw back in my hands for under $300, it's a steal if ya ask me but I know he cuts me a great deal because I'm a "commercial" customer.

However I've learned a lot of tips on what everyone here is doing with their gas mixes and I think that was the cause of my 660 chipping the head of the piston on the exhaust port side. So I'm going to mix my fuel a little richer for a while and see what kind of performance I can see.

Ok wow that must have been one he$$ of an air leak . The $300 price seems super reasonable to put it back together.

 

[Tree Student]

Ok wow that must have been one he$$ of an air leak . The $300 price seems super reasonable to put it back together.

He said the seal was really rough when he got it apart, I'm sure my guy just kept running it until it wouldn't run so it only made matters worse however he knows better now lol.

 

[Andyshine77]

I bet your guy got the bar stuck and started tugging and pulling on that saw like a mad man, you need to teach him how to use a saw properly, and how to get the saw unstuck without tugging on it. It really sounds like this guy shouldn't be running a saw at all if you ask me. Does he ware any PPE?

 

[Tree Student]

I bet your guy got the bar stuck and started tugging and pulling on that saw like a mad man, you need to teach him how to use a saw properly, and how to get the saw unstuck without tugging on it. It really sounds like this guy shouldn't be running a saw at all if you ask me. Does he ware any PPE?

That may have happened but great help is very rare to find down here and good help is even hard to find so I take it when I can. I know I could use more teaching as well as he does but if I have to buy a few parts here and there to learn on my own then so be it. I'm still profitable and he's still making me money so at the end of the month it isn't as hard as it is when I'm getting handed a broken saw lol.

We wear most PPE for our work, when cutting firewood it's gloves, goggles, and chaps with long sleeves.

 

[Andyshine77]

I glad to hear PPE is used.

I'm going to guess that at some point the saw was ran lean and or improper fuel mix. Make sure the shop checks the rpm's before you start running the saw, after the rings seat you will need to recheck the max rpm's.

Running more oil will keep the seals wet and give you a wider margin of error when your mixing up your fuel.

 

[Ray Bennett]

So I'm going to mix my fuel a little richer for a while and see what kind of performance I can see.

That is a good Idea, However keep in mind more oil means less gas which may make your saw run leaner and rev higher. Some folks can not understand this but I had a friend blow his saw running 32:1 and not reseting his H jet to compensate for the different mixture. 40:1 may not make a noticable difference but with your recent luck and inexperienced crew I would definatly have The H Jet turned out a little extra to compensate for misuse.

 

[Andyshine77]

Running 32:1 or 40:1 will have very little effect on the saws rpm's, the temperature will effect the rpm's more than the oil, that's why I think you need a tach so you can periodically check you saws rpm's. And yes run them under the max rated rpm to be safe.

 

[rupedoggy]

Hey Ray Bennett just for the sake of argument, how much oil would I have to run to blow a saw from being too lean? How about 1:1? If you think your theory is true-- try it. I would like to hear your report back. If your idea is true the darn saw would scream on straight oil!
Now try it at 500:1 and see how rich it is (don't try it long LOL)

 

[Ray Bennett]

Hey Ray Bennett just for the sake of argument, how much oil would I have to run to blow a saw from being too lean? How about 1:1? If you think your theory is true-- try it. I would like to hear your report back. If your idea is true the darn saw would scream on straight oil!
Now try it at 500:1 and see how rich it is (don't try it long LOL)

There is a point of diminishing return on oil mix. Giving the saw more oil gives it less gas. This will slowly let the saw gain a few RPM's until the saw looses R's because the oil prevents proper combustion of the fuel. Andyshine made a good point that I left out about the weather which will affect the saw more than a little extra oil. Other factors would include dull chains, Ethanol, I could go on and on. I was just trying to let a guy that has had some tough luck with saws in on another factor that will affect his saw. If the shop tunes his saw on 50:1 on a real cold damp day, he may need a different adjustment on a 100 degree dry day with an employee using a dull chain and 32:1 mix. I realize the theory sounds wrong but I think others here will agree.

 

[rupedoggy]

Ray there are enough guys on this site that you could get some of them to go along with turkey manure being a good gas additive.

 

[Ray Bennett]

Ray there are enough guys on this site that you could get some of them to go along with turkey manure being a good gas additive.

Ok, some reputable people will agree. As for turkey manure in the gas, That is silly! Everyone here knows that opossum spit is the best gas additive!

 

[Haywire Haywood]

Ever try to collect fresh turkey manure? Tough to say the least. They almost never wear colostomy bags.

Ian

 

[Andyshine77]

. If the shop tunes his saw on 50:1 on a real cold damp day, he may need a different adjustment on a 100 degree dry day with an employee using a dull chain and 32:1 mix. I realize the theory sounds wrong but I think others here will agree.

Yes a 2-stroke engine tuned in the cold will run rich in warmer temps.

Ray try going from 50:1 to 32:1 and see what happens, you'll be surprised.

 

[super3]

There was a report on another site that some batches of "10% ethanol" gas was tested/analyzed and found to have greater than 25% ethanol. That would cook most two strokes unless you had a lot more oil in the mix.

I filled two 55-gal drums with pump premium before the switch to corn fed and am about out of the good stuff. I don't use that much fuel so next time I'm filling up the drums at the airport. If I pay $1.50 more a gallon I'm still ahead if it avoids cooking just one saw. Another plus is the mix and the raw gas itself has a longer shelf life.

If I can sneak some samples in at work I'll try to check some of the local corn fed for alcohol content.

Any gas is only good for no more than 30 days and this is if it is in a tight sealed "metal" container

 

[djohn]

Feel for you on the 066. I have a p/c that looks just like that. Straight gas by the previous owner. Now the fastest running saw anyone in my family has ever been around. Good ole' red eye.

 

[kevlar]

I have an old maculloch that runs at 10 to 1 and it still has the original top end.

 

[Ray Bennett]

Yes a 2-stroke engine tuned in the cold will run rich in warmer temps.

Ray try going from 50:1 to 32:1 and see what happens, you'll be surprised.

I like 32:1 That is what I ran in all my stihl's when I was using their normal oil. Recently I tried thier synthetic ultra and backed the mix to around 40 to one. 50 :1 makes me too nervous. Im sure it is fine but my first Homelite ran 16 :1 and like kevlar's saw it is still running. I got used to that dark green gas and can not pour 50:1 in my saw

 

[motosierra]

There is a point of diminishing return on oil mix. Giving the saw more oil gives it less gas. This will slowly let the saw gain a few RPM's until the saw looses R's because the oil prevents proper combustion of the fuel. Andyshine made a good point that I left out about the weather which will affect the saw more than a little extra oil. Other factors would include dull chains, Ethanol, I could go on and on. I was just trying to let a guy that has had some tough luck with saws in on another factor that will affect his saw. If the shop tunes his saw on 50:1 on a real cold damp day, he may need a different adjustment on a 100 degree dry day with an employee using a dull chain and 32:1 mix. I realize the theory sounds wrong but I think others here will agree.

Weather conditions definitely affect internal combustion engines.That is why small aircraft pilots love cold dry air over hot humid air. Another example would be diesel engines. They run better in cold dry air. You can pack more fuel into cold dry air.