300R Sportmaster gearcase oil

[H2OPERF]

I looked at the msds sheets they now say mercury marine as the mfg... many companies don't bother changing the form and you can back track it. The form does say mercury Belgium, chevron does have plant in belgium and they make a really good 85w90 gear oil call geartex... So who knows. They probably don't use the same mfg for all the oils but i have used motul and their 2 stroke is probably the best out there just super expensive. I had a sheet somewhere that said one of the oils was made by fuchs but i'm sure they change vendors all the time.

[Pulsare2400]

Amsoil does make FC-W approved 100% synthetic 4 stroke marine engine oil in 10W-30, 10W-40 and semi-synthetic in 25W-40. They make a 100% synthetic marine gear oil but I only saw 75W-90, not 85W-90.

[mjw930]

I just got off the phone with Mercury. They looked it up in the Service manual (not the owners manual) and said everything has switch over to the High Performance SAE 90. In fact, they confirmed the older Extreme Performance 85W90 is no longer a current product, everything has swung over to the High Performance SAE 90 formulation.

Agree or disagree it's straight from the horse's mouth, don't shoot the messenger.

HOLD OFF, I called again and made sure I got to someone in Mercury Racing and they confirmed the factory fill on Sportmaster is the High Performance SAE 90 but it's perfect OK to run the Mercury Racing Extreme 85W90, just DO NOT mix them. They didn't say you had to flush the lower, just completely drain before you refill. They also said the Extreme is considered a better lube but not needed on the new case based on long term testing.

[Pulsare2400]

Wow, so i do have the wrong gear oil in mine and enough left over to change it 3 more times! I might have to scrap it then. I might ask them if it is still acceptable to use and if the new stuff has just superceded the old one. Glad you called them because i have seen internet posts saying the SAE 90 is the old formulation and the Extreme was the new which apparently is incorrect.

[mjw930]

See my update, you're good!

[H2OPERF]

So they put marginal oil in an $8000 gearcase out the door, then say u can use the good stuff if ya want... amazing.

[mjw930]

So they put marginal oil in an $8000 gearcase out the door, then say u can use the good stuff if ya want... amazing.

I disagree with your premise, that's not what they are saying. What they actually said was their ongoing testing showed that the High Performance Gear Lube provides excellent performance and protection, well within the factory specifications. When the owners manual was produced they did not have the long term results so they errored on the conservative side and recommended the Extreme Performance blend already on their shelves. When the Service manual was produced they had the long term results and updated it to reflect High Performance meets their requirements for ALL outboard lower units. Calling it "marginal" with no actual knowledge of the formulation or performance results is simply wrong.

They also confirmed that on paper the Extreme Performance formulation was superior and you were certainly free to use it but there is no real world evidence it will protect the lower unit any better than their High Performance lube. Basically use whichever of the two you prefer but understand neither will damage your lower or void your warranty.

It reminds me of the years of arguments on thousands of motorcycle forums regarding what's the best oil to put in your, Harley, BMW, Goldwing, etc with doom and gloom stories about your bike blowing up if you didn't use the $15 / QT latest and greatest synthetic JASO certified liquid gold only to find that $20 / gallon Shell Rotella T6 outperforms all of them in the real world.

[mjw930]

So, after all this and Mercury saying it had the green stuff in it from the factory I drained it today and honey colored oil came out. Luckily I had some racing extreme on the shelf so that’s what went back in. I’ll save the green stuff I bought for the TMII on the Key West.

You can’t make this stuff up.....

Oh well, at least what came out after 30 hours looked real good.

[Pulsare2400]

Interesting. When I drained mine around 28 hours, green colored gear oil came out (factory fill) and I put the Extreme Performance honey colored back in. My 300R was manufactured around April 2019. It sounds like Mark's factory fill was the honey colored gear oil. So if Mercury put two different gear oils in his and mine, like other members have mentioned, I don't think Mercury is concerned that one or the other will void warranty requirements.

[mjw930]

Interesting. When I drained mine around 28 hours, green colored gear oil came out (factory fill) and I put the Extreme Performance honey colored back in. My 300R was manufactured around April 2019. It sounds like Mark's factory fill was the honey colored gear oil. So if Mercury put two different gear oils in his and mine, like other members have mentioned, I don't think Mercury is concerned that one or the other will void warranty requirements.

It probably depends on when it was built, mine was part of the first wave in 2019 so they apparently switched over at some point. And to clear up another piece of miss information, the Mercury Racing Extreme gear lube is still a current part number.

All this is interesting since back in the day the only thing that would keep our old Bravo 1 lowers from hand grenading once we got past the 500 HP mark was Red Line Heavy Shockproof. That and a whole bunch of IMCO parts.