the fed law prohibits requiring a specific brand
the manufacturer can however require certain specifications like 4M f-CW
that said, i agree with fred67. I havent ever seen a failure due to oil failure that has been changed regularly.
synthetic oil is also fine, as long as teh engine has over 100 hours on it, but totally overkill, since we dont see engine failures due to bad oil quality.
change the oil and filter regularly. use an oil rated for the application.
Towboat is changing out some motors with close to 4000 hours on them, and he doesnt use yamalube, and has never had a failure due to oil
back to the original post…
oil isnt going to be an issue.
most common problem would be dirty fuel/carb