Synthetic Oil in Lower Unit?

[Ken]

I'm sure this has been discussed before, but I would like to some recent experience comments.
I'm considering replacing the lower unit oil with synthetic (Mobil 1). I've used their motor oil in my trucks for years, and really like it. They make a synthetic gear oil that should work well in the lower unit of my C115. You can't wear the stuff out, and I figure just loosen the lower plug every now and then and check for water intrusion. If none, then just top off the level if needed. No need to drain the oil every season.
My only concern, is the compatibility of the synthetic oil with the seals and gaskets of the lower unit. Any comments would be appreciated.
Ken K
Beaumont, TX

[Hamfisted]

Hey Ken, I've been using synthetics (Mobil One) in my lower unit for over 15 years and never had a problem with seal leaks caused by the oil. Last forever and water won't mix with it.


Mike........ Miami, FL

[Ken]

Thanks, Mike - do you flush the synthetic on a regular basis, or just check it for water intrusion from time to time?
Ken K
Beaumont, TX

[Hamfisted]

It's cheap insurance to change it out every season, but you don't have to.


Mike