Does 2 stroke oil ever go bad if unopened?

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  #1  
Old 06-27-10, 05:20 PM
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Does 2 stroke oil ever go bad if unopened?

The guy who I got my boat from has a case of Valvoline 100:1 outbboard oil, that is all that he ever ran. The case is 10 years old, he was wondering if it were any good and could it still be used? I planned to use some sort of a synthetic, not sure if the Valvoline would go bad or not, I'm thinking not if unopened and unmixed. If it's 100:1 it must be synthetic as well.
 
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  #2  
Old 06-28-10, 04:01 AM
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Oil has a long shelf life if unopened . . . once opened, the additives in oil can cause it to turn acidic if poorly sealed (thatís the reasoning behind why manufacturerís suggest changing oil not only based on usage (i.e., mileage or hours motor has run) but also on the basis of time if motor is seldom used). Concerning what constitutes ďlongĒ shelf life is dependent on storage conditions . . . if stored where it is subject to extreme temperature changes (e.g., a poorly insulated shed) w/ say temp. ranges of 40-110 F degrees, that would be more concerning than if temp. fluctuations were more moderate. Oil stored for a decade seems to be stretching it . . . if you opened it, and found it was either lumpy or had a rancid smell you know that it is bad. Since an outboard is expensive, I would not bet my outboard engine over several bottles of oil involved w/ an oil change. If this involved old oil for an old dilapidated weed wacker, I might be begging for an excuse to buy another one.

Based on what you posted, it seems the outboard engine must be at least 10 yrs. old. If for some reason itís not, you should check the engine oil specs as the old oil may not meet the technical requirements for newer engines.

I would be skeptical of the storyline this guy told you. If truthful that Valvoline 100:1 outboard oil is all that he ever ran, then it begs a question as to why a 10 yr. old case remains. Questions raised in my mind . . . did he buy a boatload of this oil 10 yrs. ago, and down to his last case (doubtful), never rotated his stock (possibly), or rarely changed the oil (concerning).
 
  #3  
Old 06-28-10, 07:02 AM
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Rob, the outboard motor is a 1977 Merc and the boat has not been in the water for 10 years. The guy who owned the boat and the oil is my next door neighbor who was an avid boater until the boat became in need of repair. I recently acquired the boat and I'm in the process of restoring it. The case of oil has been stored in his unheated/uncooled integral garage and none of the seals have been removed.... I'm assuming that it will have one of those aluminum seals under the spin off cap.

I'm in total agreement about not chancing it if there is a doubt.
 
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Old 06-28-10, 08:23 AM
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Hi HotRod,

Wow, 1977 . . . thatís an oldie goldie! At least you know the history of the boat & engine.

I would pop the seal and pour it into something for reuse just to see its condition. If it seems okay, perhaps you could use some short-term if planning to run and test engine before putting it to harder use, and then drain w/ fresh oil put in. I just donít know of a way to be absolutely certain if okay or not other than subjecting it to an oil analysis which would not be cost effective. Some people use old oil as bar chain oil on their chain saws . . . but thatís not such a great idea as lower viscosity can burn the chain. I sometimes use old lubricants on non-mechanical stuff like spare mower blades to keep íem from rusting up but your quantity would last me a lifetime. Iím sure you hate to waste it.

Have fun w/ your restoration, and please post back before & after photos. Youíll really feel great if coming back to dock w/ a load of fish, and watching the guys w/ their fancy, shiny new toys wonder what theyíre doing wrong. As a kid in Miami, I remember the chatter among the older guys wondering how the Cubans in their dilapidated boats and using hand lines could catch so many fish.
 
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Old 06-28-10, 01:22 PM
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Rob, I guess one of my other concerns is that oil technology may have changed in 10 years, good oil back then may be crap today. Maybe I'll use it to lube the cylinders before restarting it, no fire in 10 years...

Oldie is right...LOL. Its basically a ground up rebuild on the affordable side. So far, gutted to the hull, new floor, fixed the wiring, new transom ready to go in, new bilge pump and livewell pump, new trailer lights/wiring/tires, new cover, new and improved power center, new dash, new carpet going in this week, new paint inside the hull, new seats to follow. The 50 hp Merc 500 will be fixed if it ONLY needs a lower unit, if not I will be replacing it completely with a new-to-me motor..LOL

Here are some starting out pics:


http://i154.photobucket.com/albums/s...nrightrear.jpg
 
  #6  
Old 06-28-10, 05:06 PM
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HotRod, You wonít go wrong w/ that boat . . . itís virtually indestructible unless running high speed into a rock or dock. The 50 hp Merc should make that light boat fly.

Back in the 60ís, I bought a 14í V-hulled aluminum Starcraft boat w/ 9-1/2 Johnson. It resembled this 1970 Starcraft Marine 14' Aluminum Fisher for Sale - iboats.com . . . I was shocked to see that Starcraft is still in existence, and how many boats from the 70ís were for sale . . . proof of their durability. Mine was smaller than yours and no steering console, but it was a great boat for fishing the Everglades, Biscayne Bay, and backwaters of FL Keys. Since those days, Iíve owned sport fishing boats . . . and now only own a small canoe (howís that for downsizing?). I occasionally think about buying another power boat, and if I did, it would be something in your size range . . . the sport fishing boats chewed up far too much time preparing to go offshore, and constant maintenance and repairs.

If youíre used to heavier fiberglass or wood boats, youíll find the aluminum hull to be lighter, and handles differently. I was hot dogging w/ another friend in his boat, and flipped mine on a sharp turn over his wake . . . really dumb as I lost some of my fishing tackle but not the stupidest thing I did as a teenager. Great memories, though.

Originally Posted by HotRod53F100 View Post
I guess one of my other concerns is that oil technology may have changed in 10 years, good oil back then may be crap today.
I donít think thatís a concern based on what Iíve read and others have said. In my earlier post, I wasnít sure how old your engine was, and reason for citing that concern. As I understand it, so long as the engine was made to burn that grade of old oil, you should be fine assuming the engine oil is still good. The problem comes when some one buys a newer engine that requires certain oil specs, and the person uses old oil that donít have the needed additives. While weíre on this, I remember a buddy with an older outboard telling me of problems he had encountered by using modern fuels w/ ethanol as an additive. I wasnít paying close attention to his details, but the alcohol was dissolving (damaging) fuel system parts made of black neoprene rubber. I think he was saying so long as the ethanol mix was 10% or less, it was okay but the transport drivers putting in the additive are not always meticulous w/ ethanol going over 10% sometimes . . . and something about the fuel w/ ethanol breaks down quicker w/ his mechanic recommending a stabliizer. Might be something to ask about of someone more knowledgeable than me.

Really hope you have great fun using it!
 
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