40 weight 2 cycle oil?

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Mar 21, 2005
Elderly County, Florida
Good evening fellow oilers: Scored two (2) 16 oz cans of "Shell Super Outboard Motor Oil" "50 to 1" "SAE 40" I'm confused on how to use this stuff. It's rather old,(it comes in a metal can with the old pop-top can lid like beer cans back in the 60's & 70's. So I'm figuring this oil is at least 30 years old. The can is entirely too rusty and faded to put on E-bay so I'm going to use this stuff in my old weed eater. The directions on the back say: "Pour 1 U.S. gallon of gas into empty 6 U.S. gallon tank. Add 1 pint of oil. Replace cap, shake vigorously to mix well. Fill remainder of tank with gasoline." The thing that has me really baffeled is the "SAE 40." Is this a 40 weight two cycle oil? Can I just mix a 32 to 1 mixture like I normally would with modern day two cycle oil? Like James Brown, I just have to say: "Somebody help me!"
The only thing I would use it for is to fill up a plastic bag as I took the cans to an oil recycler. WeedEater motors usually need 40:1. If you need oil bad enough to use 30 year old stock, I think the board will take up a collection to buy you 4 new bottles from Wal-Mart for $2.00, total. [freaknout]
I can't answer your question ..but PZ 2 stroke is a 30 weight. Perhaps that's why it's a 50:1 deal as opposed to a 32:1 or 40:1. One could reason that there would be a dilution/viscosity deal going on [I dont know] I hope that someone with more intimate knowledge of 2-strokes chimes in here. I don't see why you can't use this if you get the ratio issue resolved.
a long, long time ago, in an what seems another lifetime, (almost twenty years ago.... [freaknout] ) I raced karts and we used Castrols (then) excellent R30 and R40 castor based oils. The 30 and 40 did indeed relate to their respective 'weights'. I think dilution rates relate more to things like piston scuffing (or seizure) main, big and little end lubrication, etc. IIRC, we used to use 16:1 (??) in our IAME Parilla and PCR engines using R30, which were pretty highly stressed reed and rotary valve engines doing some serious revs (16 000+), yet used 40:1 in my original Yamaha 'J' (I'm guessing here) only pushing around 10,000RPM using Agips excellent 2T or Castrols TTS (both synthetic)
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