300R Sportmaster gearcase oil

[mjw930]

Oops, I misread something else regarding the difference between gear lube and motor oil viscosity so you are absolutely correct. So, it would indicate the additive package used in extreme has a broader range of temperatures it’s rated to operate in as it would be considered multi-vis vs. straight weight.

Either way a call to Mercury Racing seems to be in order just to confirm. I’ll wait on doing the lower until I talk to them.

[H2OPERF]

The racing oil is quite a bit more expensive so i hope there's more pressure additives or whatever to make it worth the money. The race oil is multi grade or it would only have one grade number... The only reason i can think of for the multi grade is they use in the big drives with lube pumps so maybe in cold water they need the 85w. I was told at one time it was made by fuchs... grade and weight are the same thing i think grade is the proper term.

[mjw930]

The racing oil is quite a bit more expensive so i hope there's more pressure additives or whatever to make it worth the money. The race oil is multi grade or it would only have one grade number... The only reason i can think of for the multi grade is they use in the big drives with lube pumps so maybe in cold water they need the 85w. I was told at one time it was made by fuchs... grade and weight are the same thing i think grade is the proper term.

Yes, I keep forgetting the “W” in the grade scale = Winter, aka cold viscosity, not weight. I got confused reading an SAE abstract that was pointing out grade 90 gear lube was roughly the same viscosity as 40 weight motor oil. We all tend to use the term weight wrong when we talk about oils.

[TraceF3]

Oops, I misread something else regarding the difference between gear lube and motor oil viscosity so you are absolutely correct. So, it would indicate the additive package used in extreme has a broader range of temperatures it’s rated to operate in as it would be considered multi-vis vs. straight weight.

Either way a call to Mercury Racing seems to be in order just to confirm. I’ll wait on doing the lower until I talk to them.

Cool. See what Merc says and I'll call a Shell insider and see if he knows and can tell me anything.

[H2OPERF]

I still use weight, in the first post i put 90w for 90 weight, lol. I called mobil oils asking about mobil SHC 626/627 a gear oil we use in helicopter transmissions that i had been using in my gearcases bc i got it free, its a full synthetic but graded under iso so i wanted to know what SAE grade would be equal to the iso grade... anyway got lucky and talked to some gear oil guru and he asked what the diameter of the gears were/hp ant gear type etc.. when i told him what i was using it in he said the shc was an industrial oil that would be fine for the loading but those oils are not good for shock loads. I told him i wanted full a synthetic and the merc racing was not... he said you will never get a full synthetic to perform under extreme pressures with shock loading and unloading like a boat gearcase will see you will need a blended oil. He gave me a few oils they had that would work but all were about the same price as the merc racing so at that point why bother. Dave

[Pulsare2400]

I am not certain if gear oil is the same nomenclature. For engine oils a 20W-50 means 20*C is the lowest temperature it will pour at and 50 means it will have a viscosity of 50 at 100*C. Or a 5W-30 will pour at 5*C and have viscosity of 30 at 100*C. So I remember having a differential in one of my trucks that asked for 90W - 140 Mobil 1 synthetic gear oil, not sure if that works the same. I am also not sure of how they define "pours". I used to build and own drag cars. 20*C is about 68*F, and we used 20W-50 oil if we were running .003 - .004 bearing clearance. I know I had no issues "pouring" 20W-50 oil at much lower temperatures than 68*F. However they might define "pour" as emptying a certain amount of oil, through a certain diameter opening in a certain amount of time???
Let us know what Mercury Racing says, but I feel fairly certain that the Extreme Performance is one of their better gear oils.

[TraceF3]

Yep. It's all about the spec. That's what's most confusing to me about these "private label" super gear oils Merc has. No real spec published. The HP 90 bottle for example says meets GL-4. That spec dates back decades and GL-4 has LESS extreme pressure additive than GL-5.

Typical consumer is brand loyal. Swear by Castrol or Valvoline or PZL. I go by spec. On the shelves in my barn I've got Pennzoil, Shell, Lubri-Moly, SuperTech, even STP oil. Whatever is cheapest when I need it as long as it meets the spec. I used to have access to free oil analysis and never had any "issue" with a one brand versus another. People in the industry all know this. Doesn't matter what color the bottle is.

I used to change the l/u oil in my offshore boats every 75-90 hours but I'd check it frequently to be sure it didn't show signs of water. Occasionally I'd go over 100 hours. I used whatever pail of 80w90 I could get at the local parts store. Never an issue in several thousand hours of service over the years.

Nice thing to me about the Merc HP is the water splitting additive. No milk. That could save a lower!

[Pulsare2400]

I think my post is not quite correct, in that the first number refers to the viscosity at 0*F, so a 20W-50 oil has a viscosity of a 20 wgt. oil at 0*F and the viscosity of a 50 weight oil at 100*C or 212*F

[TraceF3]

Just got off the phone with an old friend retired from Citgo. Citgo used to make Merc products 20-30 years ago. They were considered premium products then too, especially the 2-stroke oil. He thinks they went to Motul after Citgo but he isn't sure. And no idea who has the contract now. Lowest bidder.

FWIW Motul is the current supplier to Suzuki, 4S-W. And Motul is considered to be a very good product in the industry.

[Pulsare2400]

I wanted to switch my 300R to 100% synthetic but the manual says not to use 100% synthetic but Amsoil makes a 10W-30 100% synthetic that meets the FCW specs Mercury asks for. So for warranty purposes I just bought the Mercury semi-synthetic 10W-30. I just saw that Mercury came out with a 100% synthetic 4 stroke oil for the 360 Formula V8 and sterndrives. So I wonder if they accept 100% synthetic now in the 300R?

[mjw930]

I just did the oil change in my 300R with about 30 hours on it and it was ugly. Didn’t appear to be much sheen, usually a good sign of very fine metal particles but I may cut the filter open anyway. It was dirtier than I expected, I can’t image running that for 100 hours. I did the Merc semi-synthetic and am not really concerned. Although I’m a firm believer in full synthetics that term has been so watered down since they allowed cracked Group III in. My change intervals will be half the factory hours simply because I don’t put high hours on it.

I will say the drain system and the filter position are perfect, it was the easiest 4 stroke boat motor oil change I’ve ever done. Big thumbs up to Mercury. I DON’T look forward to the 300 hour alternator belt replacement.

[Pulsare2400]

I changed mine at about 26 hours and I thought it looked dirtier than it should but that was also from break-in. I typically run about 45 hours / year so I might try 45 hours next time since it is broken in, to see what it looks like. I agree, with you, a very easy oil change and no mess with all the drains they put on the engine. My manual says to change the alternator belt at 300 hours which would be 6 seasons for me. I doubt I will own the engine that long.

[mjw930]

I corrected my post, belt is 300 hours.

[TraceF3]

Spoke with SOPUS today. Neither Shell or PZL/QS know who is blending Mercury products these days. And they'd like to know as much as we would. They keep a working list of all the private labeling they can.

Had a 20 minute conversation with an old timer (36 years) and we went through the Citgo and Motul history but it dies off after that. I'm gonna try Ashland tomorrow to see if they'll tell me anything.

[TraceF3]

Well I'm no closer to knowing who makes the gear oils for Mercury but I have learned this.

Chevron tells me they do not make ANY private label product. Ashland/Valvoline either didn't know or wouldn't say. As I said earlier Shell doesn't know.

The NMMA lists only three companies making approved FC-W additives: Shell, Infineum, owned jointly by Exxon Mobil and Shell, and Oronite owned by Chevron. So it's 99% sure that's where the additives source.

According to the NMMA 2020 FC-W® Registered Four-Stroke-Cycle Marine Oils approved list there is only a half-dozen approved products in a 25w40 blend. Only two are manufactured by companies that have a large presence in the US: Motul and Penrite. They also blend 10w30. The other companies are based in Brazil, Europe, etc. Motul does make private label products; Suzuki and possibly Yamalube.

I doubt Mercury would source the 10w30 and 25w40 from different suppliers. Doesn't make sense economically or logistically. Based on all of this I think a reasonable conclusion is that Motul probably makes the Mercury engine oils. I have a message out to them to see if they will confirm or deny.

I did call Mercury tech support and I was told that "they" don't tell us who makes our lubricants.

If I find out anything substantive I'll post it.