I have a 1980 model evinrude, model TLCSA 115 hp, and am changing lower end grease. What i was wondering was is there some type of solution that i could use to flush the lower end to clean it before i replace the new oil? Thanks, Buddy.
I really have no idea if there is a product for your specific request but I would think any light oil would be a possibility as long as you drain it completely before running again. Maybe even 5w30?
For the record, if the oil is contaminated you need to fix the problem not the symptom. Otherwise a yearly gear oil change should be all you need to keep it clean.