2-cycle oil for Yamaha outboard - too old?

I don't get to get my boat out as frequently as I like and my Yamaha 150 has a reserve oil tank on the boat that refreshes the on engine iinjection system. The Pennzoil Synthetic Blend has been in the reserve tank for oprobably 2+ years. Is it safe to continue using it or should I draiin the tank and replace with new oil? Takes about 2 gal,

 

The oil itself won't break down, but the additives will separate and collect at the bottom. Google searches say that in the bottle on a shelf the oil will last up to 5 years and will need to be mixed to re-integrate the additives. Why take a chance with thousands of dollars in potential repairs?

My concern with using that Pennzoil would be the lack of additives for a marine environment. Yamaha makes an oil specifically for their engines that has corrosion protection. It costs more, but the difference is nowhere near the cost of engine repairs.

I would drain the Pennzoil out of there, replace it with a proper marine-rated oil, and use the Pennzoil in the lawnmower and snow blower.

 

Rick, thanks for your response. The PennZoil is Marine grade for 2-cycle outboards. Meets manufacturer's specifications. However, based on your logical comments, it will be a lot cheaper to just drain and replace the oil vs big $ repairs.

Thanks, again.