I am about to change the lower unit gear oil for the first time. I have a late 90’s yami 2 stroke 60. I got the proccess figured out but what about the oil, I use royal purple in my truck and saw they have a royal purple 75W90 gear oil that says you can use on lower units, any advise on oil type, would like to spend the xtra and get quality stuff? Also the seals behind the upper and lower screws, are they standard? I read you should replace when you change oil? I live in the mts where there is no west marine or any other shop so i gotta order most everything. Thanks for the help!
Yamalube is what Yamaha recommends, but royal purple or most lower unit oils will work fine. Most people recommend you change it every year. Just remember to fill from the bottom until it runs out of the top hole. Those seals normally don’t need to be replaced unless they are cracked or pretty old.Just keep an eye on them throughout the year to check for any leaks.
'06 Mckee Craft
184 Marathon
DF140 Suzuki
Mercury high performance gear oil is a good LU oil
This is what I use in mine.
http://www.amsoil.com/storefront/agm.aspx
I prefer a synthetic oil. My fuel economy is MUCH better since making the switch from Yamalube to Amsoil.
My $.02
“If the Arabs put down their weapons today, there would be no more violence. If the Jews put down their weapons today, there would be no more Israel .” Benjamin Netanyahu
Ecclesiastes 10:2
GW 205
F200 Yam
quote:
I am about to change the lower unit gear oil for the first time. I have a late 90's yami 2 stroke 60.
Ya reckon it’s about time 
I’d change it once a year at least, that way if you have any water intrusion from bad seals, the water wouldn’t sit in there 12 years before you know about it:wink: Changing it regularly is a lot more important than what type oil to use in it.
Capt. Larry Teuton
Cracker Built Custom Boats
Marine Surveying & Repair
Synthetic for me-been using it for several years now-works fine-doesn’t separate from water-mixes with it-less pressure on the seals.
“Watch what we do, not what we say.” John Mitchell
Sea Hunt Triton 202
Yammy 150
So it would seem that amisol is better than yamalube? so amisol is a synthetic while yamalube gear oil is not? When i first got the boat and knew less than I do now I ran quicksilver once (2 stroke) learned that not a good choice and immedicately switched to yamalube but I guess the rules are a nbit different for the lower gear oil? thanks for all the help!
If it swims throw a fly at it!
Oh yea well its a late 90’s yamaha but I have had it 3 years, and it got a brang new lower unit last year sooooo it hasn’t 12 years waiting for a change!
If it swims throw a fly at it!
Sure glad to hear that
Capt. Larry Teuton
Cracker Built Custom Boats
Marine Surveying & Repair
OK so i have been reading all over the internet and the consencus here is that amisol is better than yamalube because it is a synthetic. So now my wuestion is what weight to buy for a 60 hours 2 stroke, should I get the Amisol 75W-90 Or the 80W-90 ?? Does it matter, and if so why?? thanks again for all the assistance just trying to learn to do stuff myself!
If it swims throw a fly at it!
yamalube is synthetic blend, but not full synthetic, according to yamaha
Mountain Guy, the link I posted toward the top is the ONLY Amsoil marine gear lube that they sell. It is rated 75/80W - 90.
“If the Arabs put down their weapons today, there would be no more violence. If the Jews put down their weapons today, there would be no more Israel .” Benjamin Netanyahu
Ecclesiastes 10:2
GW 205
F200 Yam