Chainsaw with scored piston. How?

[ruffdog]

I decided to overhaul a couple of 2 strokers, a chain saw and weedeater. Afterwards, I decided that the only reason I was experiencing engine damage was that I wasn't getting enough lubrication. So, in buying new replacements, I still use synthetic oil and rather than 40 or 50:1, per the mfgrs recommendations, I run more like 25-30 to 1 (rather than a bottle to a gallon, I use a bottle and a half per gallon) and being synthetic, smoking is seldom visible. We'll see how that works out as the machines age.

Just remember, when you change the oil ratio, you are also changing the fuel/air ratio. With more oil, you are LEANING the amount of gasoline in the mix. Think of it this way, the fuel jet only allows so much liquid through it and if there are more oil molecules, there are less gas molecules. An already lean engine is really going to suffer with that oil ratio unless the carb is modified.

 

[EddieWalker]

Fix it yourself, pitch it or you can go this route...View attachment 581835

Amish chainsaw.

If I saw this for sale, I would probably buy it!!!!

 

[ericm979]

Yes, though the difference is small and should be in the range of the carb adjustment screws or M-tronic.

I've found that 50:1 with high quality synthetic oil works fine. For milling I'd use a somewhat richer oil ratio. 25:1 is a waste of oil and will cause excess carbon build up in the engine.

 

[TractorGuy]

No way I would spend $500 on a $725 saw.

I'm another proponent of cheap saws. I don't use a saw all that much but I've only owned 4 in my life.

The first of those was my granddad's old Whitehead bow saw. Couldn't find parts for it or I would still have it.

I bought a 16" Craftsman that still ran good but I could no longer buy the chain components for it's "Barracuda Chain". That was one badass little saw. Cost was less than $150.

I have a commercial grade Poulan bow saw in the shed that needs carb work but I have no need to use it. Bought it used for $40 and replaced fuel lines and chain when I bought it. It has so much compression I have no desire to try to start it any longer. When I had it running it would cut through water oak that was so hard the chain would throw sparks off the tree but it would walk right through it.

My 4th and final saw is a 18" Craftsman I bought 8 years ago for less than $150. It starts on the second or third pull every time I pull it out of the case. I mix my own fuel with ethanol free gas and whatever brand of 2 cycle oil I have laying around. Keep a sharp chain on and it will cut anything I want to mess with.

In summary I'm coming up on 67 and have invested less in saws in my lifetime than your dealer wants to repair this one.

 

[hawkeye08]

I have a chainsaw bought new 35 years ago, used it to get 10 cords of firewood for perhaps 10 years, converted to pellets, used saw occasionally. Last time I wanted to use it, it did not start right up (always put fresh gas in before use), figured the lines needed replacing. I might get a battery or electric one for my very occasional need. Dad wanted to take it to his mechanic and get it fixed, but hearing about work that mechanic does, didn't want to pay for a new saw in repairs.

When we bought our Stihl trimmer, the sales guy recommended priming every time the trimmer is started, even it is warm already. His story was it is important for lubrication more than fuel.. doesn't hurt anything that I can tell, so why not?

 

[stevem5215]

I have a CubCadet EFCO manufactuered saw. EFCO is the largest manufacturer of chainsaws in the world. Just not as popular over here in the states. Mine is a 52cc and has more hp per cc than the Stihl's do. It's a 20" bar on a Oregon with a D72 chain. It's really been a good saw. But one thing I always do and would recommend to anyone is to dump the old gas out and only use fresh newly mixed gas in anything 2 stroke. Old gas even a month old is junk and you get loss of Octane. That along with recommendations by saw manufacturers to use 91 Octane is important in such a small high revving engine. Also, oil is very important in them. I highly recommend Stihl Ultra as mentioned by another commenter on here who likes Stihl products. That oil has a stabilizer function in it as well and it is by far (and I've tried and ruined a lot of 2 stroke products along the way) the best oil available today. The oil and the stabilizer products used really make the carbs much more like the gas we used of old without Ethanol. If you follow these directions you will get the benefit of my years of 2 stroke use for free. I will virtually guarantee you less trouble. That and get yourself an EFCO. They make a good cutting saw. I just did 4 cords of firewood from our ice/snow storm event that stripped a bunch of trees here in Western PA. A bad deal all around. Lots of people had no power for a week. We were lucky it was ONLY out for 27hrs with a backup heating method in our basement. Others weren't so lucky.

Good luck and remember, Stihl ULTRA ! It's the way to go.

Steve

 

[Doofy]

I've never really noticed any big differences in 2-stroke oils. I use whatever is handy and tend to mix a little heavy. Homelite weedwacker is over 30 years old and the engine insides look like new. The last oil I mixed up was some Castrol from the early seventies...no problems.

 

[ArlyA]

Not sure I can tell the difference in 2 stroke oils either. How would you? The manufacturers do add chemicals so they mix well and many also a fuel stabilizer to them. We run the Echo oil variety that's partially syn and has a stabilizer added to it. Is it any better?? No idea!

I've never really noticed any big differences in 2-stroke oils. I use whatever is handy and tend to mix a little heavy. Homelite weedwacker is over 30 years old and the engine insides look like new. The last oil I mixed up was some Castrol from the early seventies...no problems.

 

[Jstpssng]

Fix it yourself, pitch it or you can go this route...View attachment 581835

Amish chainsaw.

That's a fun joke. Apparently though they are allowed to use them as long as the saw belongs to somebody else. I've been told that down in New York and Pennsylvania there are quite a few Amish woodcutters.

I've never really noticed any big differences in 2-stroke oils. I use whatever is handy and tend to mix a little heavy. Homelite weedwacker is over 30 years old and the engine insides look like new. The last oil I mixed up was some Castrol from the early seventies...no problems.

I'll keep using Husky oil until the warrantee runs out, then probably go cheaper. Although after 5 years I may want to upgrade anyways.

 

[Doofy]

It may seem odd but I like chainsaws. I still use the very first brand new Homelite Super EZ saw I purchased in 1979. I bought the Wife a Poulan 16" electric chainsaw and discovered I enjoyed the quietness when using. Several years ago, I bought a mess of saws off eBay and wound up with 3 electrics and 2 gas models that all run well. This year the Wife bought me my first cordless chainsaw. I'm 67 and don't understand the fetish.

 

[Jstpssng]

I like chainsaws when they run... when they stop I upgrade to a new one. I've only had 8 saws in my life including my current Husky and a Poulan which I use for a backup. I've used a few others on various jobs; I loved my Partner 5000, even if I did almost take my leg off with it. Oh to be young and dumb again.

 

[ericm979]

Not sure I can tell the difference in 2 stroke oils either. How would you?

Disassemble the engine, look at the parts and measure the wear. I ran Motul 800 synthetic in my two stroke road race and street motorcycles and had opportunities to examine engine parts. The only lubrication based failure was when an oil injection line on my RZ500 got kinked during installation due to my error. That piston's sitting on my desk as a reminder. In off road competition (observed trials) the smell of the Motul was getting complaints from other competitors. I switched to Redline Allsport synthetic. It also worked well with no failures and the exhaust smells better. I've continued to use it on my saws.

 

[Stimw]

I bought a case of oil for my outboard motor and just use it in my 2 cycle engines.
If it is good enough for up to $20,000. engines then it will work on those toys.
Still use Echo oil in my saw though with it's own gas can.

 

[turbo36]

Just remember, when you change the oil ratio, you are also changing the fuel/air ratio. With more oil, you are LEANING the amount of gasoline in the mix. Think of it this way, the fuel jet only allows so much liquid through it and if there are more oil molecules, there are less gas molecules. An already lean engine is really going to suffer with that oil ratio unless the carb is modified.

Absolutely correct!

 

[kthompson]

I had a smaller stihl same happened to and still under warranty but was told no warranty on that as it was my fault over heating the saw. Bull. Had friend tell me you could not have held onto that saw if it ran that hot and I agree. Two points, another shop bout parts off ebay and repaired it but did send complaint to stihl who had dealer buy it back. It had been in their shop several times for did not want to run and in the process they had adjusted the fuel mixture. Bought a model or two up and very pleased with it.

 

[JimRB]

I heard one of my neighbors running a chainsaw. Full throttle, maybe I heard the rev limiter when they were using it. Not the way I run a saw. Full throttle when I am in stuff big enough to bog the saw down a bit. I thought I had seen pictures or comments in the past about piston scuffing from unnecessary wide open throttle but maybe not. I use high test gas, Stihl oil in the silver bottle at 50-1, fuel may sit for 6 months or more. I cannot say that I have anything that will not start among the 5 Stihl engines. Heck I had 5 year old gas in my generator that started every time I did a test start which might be 6 months to a year between starts. I would turn off the fuel cutoff valve and let the engine empty the carb. No fuel stabilizers in that fuel. Yes, I play with fire. That said I have had to remove the carbs and clean them up on my Dad's equipment. I think he bought low test fuel for the mower and tractor.

 

[arrow]

Where on the piston and scoring characteristics can tell you what happened. Most saws score on the exhaust side from over heating or fuel ratio problems. Bad gas and over heat look about the same. Intake side scoring has more to do with faulty filtration.
What I saw many times in my career were saws that were using premium fuel that had a lot of cleansing additives in it. Combine this with a saw that was over revving as a result of too lean screw settings and you got washed out cylinders that quickly deteriorated.
Also, not all canned fuels are equal. Buy the good stuff from a dealer as opposed to that Trufuel crap Wally World sells.
Any saw should not be rev screaming and never tune or have tuned a saw to go as fast as it can.

 

[PILOON]

I decided to overhaul a couple of 2 strokers, a chain saw and weedeater. Afterwards, I decided that the only reason I was experiencing engine damage was that I wasn't getting enough lubrication. So, in buying new replacements, I still use synthetic oil and rather than 40 or 50:1, per the mfgrs recommendations, I run more like 25-30 to 1 (rather than a bottle to a gallon, I use a bottle and a half per gallon) and being synthetic, smoking is seldom visible. We'll see how that works out as the machines age.

A bit too much oil really wont hurt a 2 cycle other than messing up the spark plug, and that's cheap to replace.
OK, maybe a bit of smoke but that'll keep the biting bugs away. LOL.

IMO they are getting a bit to lean on the oil these days.
Engineers simply trying to meet California 'smog' regs perhaps?
Then there is the consideration that 2 strokes are by design lighter weight than a 4 stroke due to less parts.
The saw engineers fully understand that a saw user simply does not want to us a saw (4 stroke) that weighs twice the weight or a 2 stroke and is attempting to meet the smog (environment) regulations.
There is simply no way you will get 4 stroke chain saw to ever outperform 2 stroke.

Use oil and simply change spark plugs when the saw gets sluggish or hard to start.
Plugs are cheap!
Back when, the oil mixes were much richer and we never had seized or scored pistons.

 

[Texasmark]

Just remember, when you change the oil ratio, you are also changing the fuel/air ratio. With more oil, you are LEANING the amount of gasoline in the mix. Think of it this way, the fuel jet only allows so much liquid through it and if there are more oil molecules, there are less gas molecules. An already lean engine is really going to suffer with that oil ratio unless the carb is modified.

Good point but: A 124oz gallon of gas gets a 2.7 oz bottle of oil per directions on Stihl silver bottles. Boosting by 50% is just 1.35 oz or right at 1%. Doubt that will make any difference especially with my running premium fuel.

 

[arrow]

Back when, the oil mixes were much richer and we never had seized or scored pistons.

Back when, we never had chainsaws running as fast as they are now. The old McCullochs and Homelites I used to use were lucky to have chain speeds of over 8000 rpm.
With manufacturers making smaller saws with as much power as the old larger ones, speed is critical. The old saying "nothing beats cubic inches" is not quite true as rpm's can certainly over come c.i. deficiencies.
Old saws, being way slower, were much less susceptible to fuel ratios, gas quality or chemical configuration and poor or uninformed cutting techniques than exist today.

Speaking of speed. Anyone want to buy the 763 mph Blood Hound race car with the Rolls Royce jet engine? Only $250,000.