you know its bad news when your repairman brings your favorite Stihl saw back in a box with a bouquet of roses (R.I.P.). At the neighbors today when this happened. Stihl guy'd found the roses in a store's dumpster & threw'em in to make the point. Cylinder & piston scored too bad to run again. Neighbor'd let the saw sit with gas for months, then worked it till it quit on'm. Oil in gas, over time, will break down & it's like running with straight gas. Now he's got to see is his Husky quit for the same reason. If mine sit awhile I add a small amount of oil to the saw's tank just to be sure. Dunno how many times I've seen this happen.
- Thread starter 2x4
- Start date
DENNIS MIN
Member
2x4,
I have not heard that a gas and oil mix would somehow separate over time. That being said, I do shake the mixture prior to pouring it in a 2 stroke. I have not even considered an expiration date for the fuel, seeing as I use a gallon of mixed in about a week.
Where do you think the oil goees after time? I think it would stay in the fuel can, but weirder things have happened.
D.
I have not heard that a gas and oil mix would somehow separate over time. That being said, I do shake the mixture prior to pouring it in a 2 stroke. I have not even considered an expiration date for the fuel, seeing as I use a gallon of mixed in about a week.
Where do you think the oil goees after time? I think it would stay in the fuel can, but weirder things have happened.
D.
chuck machinist
Well-known Member
One of those things you do not think about until you need her. Thanks. Ill check mine today!CM
Copperhead don't play
Member
I made the mistake of using 2 cycle outboard oil in my oil and gas mixture for chainsaws. Ruined two chainsaws. Apparently water cooled outboard oil can not take the heat in a chainsaw.
showcrop
Well-known Member
With the coming of methanol gasoline the use of dry gas became pretty much a thing of the past. What the dry gas does is dissolve the water so that it is thoroughly mixed into the gasoline and can burn. methanol gasoline does this for you. If you have methanol gasoline sitting for long periods of time the gasoline absorbs moisture from the air again and again, so of course it becomes more water and less gasoline. There is also a reaction that produces soap and an insoluble gelatinous substance. The oil is still there, but it is nowhere near enough to make up for the high water content.
Texasmark1
Well-known Member
"Apparently water cooled outboard oil can not take the heat in a chainsaw. " OB oil is TC-W3 rated these days: TC= 2 cycle (stroke) and W
= watercraft. the 3 is just the 3rd iteration of the spec. I think you hit upon the problem being temperature as the CS is air cooled. Also I
have started to run my newly purchased saw and weed whackers at 50% higher oil ratio than recommended even though I use the best CS
oil I can buy.
Seems the single or double ring alum on alum WW and CS engines need more lube to keep the alum from wearing away, or I have been
experiencing the above mentioned problem with storage, since they don't have cast iron liners for the cast iron rings. I do use 3 types of
"snake oils" in the gas mix to assist in storage protection. Just last season I trashed the old after attempted ring replacements and other
problems with the old and bought new. Course I had an ulterior motive: Easy starting options with the new and everything else was
wearing out with the old too so why not upgrade.
= watercraft. the 3 is just the 3rd iteration of the spec. I think you hit upon the problem being temperature as the CS is air cooled. Also I
have started to run my newly purchased saw and weed whackers at 50% higher oil ratio than recommended even though I use the best CS
oil I can buy.
Seems the single or double ring alum on alum WW and CS engines need more lube to keep the alum from wearing away, or I have been
experiencing the above mentioned problem with storage, since they don't have cast iron liners for the cast iron rings. I do use 3 types of
"snake oils" in the gas mix to assist in storage protection. Just last season I trashed the old after attempted ring replacements and other
problems with the old and bought new. Course I had an ulterior motive: Easy starting options with the new and everything else was
wearing out with the old too so why not upgrade.
I believe it's more like the oil, gas, ethanol and all the additives produce a new chemical with properties that are harmful to the saw, it's fuel lines and seals, etc. If the mixture can form gum in a carb, it's perfectly reasonable to expect it can form the same gum between a ring and groove and cause minute scoring which over time gets worse. I have seen saws with no carbon build up and good seals that scored the piston and jug, even though if anything they were running a bit rich.
TomH in PA
Well-known Member
Using the cheapest dead dinosaur oil at the highest ratio is asking for trouble with today's lean running motors and ethanol gas.
Full synthetic oil mixed in E0 gas at a little higher than manufacturer spec (e.g. use 40:1 instead of 50:1) is much better.
Full synthetic oil mixed in E0 gas at a little higher than manufacturer spec (e.g. use 40:1 instead of 50:1) is much better.
Michael Soldan
Well-known Member
I have read several responses and I have a different read on this. I think that the fuel in the carb goes varnishy and it affects the fuel /air mix. That saw ran too lean and that's what scored the piston and the pot. With the clogging of the jets in the carb the fuel was not getting into the mix and air was constant causing the saw to run too lean. I have seen this happen with a year old snowmobile that didn't have the carbs drained at the end of the previous season.I know gasoline can break down in a few months but the oil in the mix is far more stable than that. I always give my fuel can a good shake before I pour to ensure its all remixed. I have never lost a small engine no matter how long it sits, I use fuel stabilizer and Sthil oil contains a stabilizer anyway...I did lose that snowmobile engine and it cost over $400 for two pistons because it ran too lean..my version and the Skidoo dealers version !
Very early in the gas/ethanol days, Methanol was substituted for Ethanol until the plants could be brought up to production to meet the demand. Methanol caused many of the problems that Ethanol was/is being blamed for. We raced a Dirt Late Model (probably the first in the country) for 10 years on E-98 and never had a problem with it. When we used methanol the carb was to be drained or run some gas through it if it was to sit for the week. The last engine I freshened was dyno run and produced 619 hp on Ethanol and the dyno owner put his Methanol carb on it and it produced 620 hp.
Steve@Advance
Well-known Member
Not sure there is a break down, but if the container is not sealed, the gas will evaporate, leaving behind the oil.
Too much oil does 2 things, it leans the mixture, that causes detonation, overheating to the point the piston swells, looses clearance and has a seizure.
The other thing that happens, simultaneously the overheated cylinder starts burning oil on the exhaust side, which forms thick residue and eventually hard carbon. This further crowds the piston clearance, resulting in more galling.
Too much oil is just as bad as too little. Looking at a variable delivery oil system, only when the engine is at full throttle will it give the max amount of oil, usually 50:1. At idle the mix drops to 200:1.
Too much oil does 2 things, it leans the mixture, that causes detonation, overheating to the point the piston swells, looses clearance and has a seizure.
The other thing that happens, simultaneously the overheated cylinder starts burning oil on the exhaust side, which forms thick residue and eventually hard carbon. This further crowds the piston clearance, resulting in more galling.
Too much oil is just as bad as too little. Looking at a variable delivery oil system, only when the engine is at full throttle will it give the max amount of oil, usually 50:1. At idle the mix drops to 200:1.
Interesting theory, that the fuel in the mix turns to varnish or gum and makes the saw run lean. That might fly with a saw where the owner isn't capable or interested in adjusting the jets. I set mine, as needed, to run properly and not lean with the fuel I'm using. I might change the setting over the course of a days cutting. Yet, I still have a very nice Sachs 133 that scored the piston for no apparent reason. I don't know the exact reason it died, but it wasn't old fuel, carbon, bad seals, lean mix or lean carb settings.
Steve, could you explain why you think "too much oil leans the mixture"? A lean mixture is more oil (or air if talking about the carb) and less fuel. I've recently started seeing people refer to having "too much oil" as causing a lean condition, but this goes opposite to everything I've learned/read/been taught in service schools over 40 years of messing with 2 cycles.
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