Hello everyone. I've never posted to this group before but I have a
question that I hope you all can help me to answer.

First, a little background info. My dad has a 1991 Yamaha 3-cylinder,
85 Horsepower 2-stroke engine on his 16' boat. The boat was just loaned
out to one of my brothers for a weekend at our cabin on the lake. My
dad later remembered that he didn't mix the fuel with oil at 50:1
before handing over the keys to my brother. We managed to get in touch
with my brother and tell him to bring the boat in, but the engine was
run for about 60 to 90 minutes without the oil mixed in.

The question here is: what special care, if any, needs to be taken in
order to ensure proper operation of the engine? Should we add a thicker
oil or some sort of treatment, or just mix in oil as usual and resume
normal operation?

Thanks for any help you can provide!

-Jared