Howdy,
A lot of us like to use a synthetic gear oil in our sterndrives. Mercury and Volvo alike suggest using (their) synthetics in the higher power drives but just about ANY synthetic is OK.
Since there is no NMMA ("marine") specification for hypoid gear oils, ANY (manufacturer suggested SAE weight, NON-limited-slip) hypoid gear oil is suitable in any stern drive.
You're changing the gear oil once a year, during winterization I suspect.
I found Supertech marine gear oil at less than $5.50 per qt. ........Mercury HP (syn) at about $16/qt (if you're seeing 4-times, maybe you should do a little "shopping")
BUT, If you're comparing apples to apples, the Mercury (Non-syn) oil is a little less than $8/qt
Your Cobra probably holds less than 3 qt? (The 460 King Cobra held 108oz which is about 3.3 qts...........32oz/qt....................)
So 3 qts of Mercury NON-synthetic oil is something like $3 more (per qt) .......... You're talking about $10 more for the Mercury(non-syn) ......(About the same as maybe 3 gallons of gasoline?)
I'm not really getting where the problem is.
If you don't like the local prices, you can get gear oil from right HERE on iBoats! Or Wholesale Marine, Marine Parts Express, Amazon, etc etc etc. Some have free shipping over certain prices yada yada......
If any particular name brand makes you feel better, by all means USE it.
Regards,
Rick
