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I've been using Canadian Tire's Castor 2T sled oil since I was a kid. Used it since my grandfather and father used it.
Some time ago, my wife told me many times to throw my AFTER sledding clothes outside / on the winter chain link fence - to air out. Ya, that Castor 2T stuff stinks really bad. And, I didn't realize it. Ouch!
Since then, I've switched to Amsoil Full Synthetic Injection sled/boat oil (regular IO since my sled doesn't have power valves) and my clothes smells much less. And being full synthetic, I was also able to "lean" the injection volume a little bit as well (for less smoke and better looking plugs). Like a human body, better food (like full synthetic blend) mean less volume for same output results. Thus, switching to Amsoil is a win-win in the long run.
Note: For Power Valve engine, I'd use "Amsoil Interceptor" mix.
Guess you can teach an old dog (me) a new trick.... LOL!