Year-round oil weight for Mercury 50hp fourstroke???

[USA_boater]

Just bought a new Tracker and the dealer filled it with 10w30 when I picked it up new. I'm planning for my first oil change after break-in and wondered if in Oklahoma I'd be better off with 10w30 or 25w40? Since the boat is under warranty I plan to use the Quicksilver oil; otherwise I'd be at least considering a 15w40 or 10w40 automotive/diesel oil.

I'll probably run this thing in the upper RPM range so the fact they don't use viscosity improvers in the OEM Mercury 25w40 (and I assume the Quicksilver too), that makes me "feel" like that would provide the better protection vs. 10w30. BUT, it can get above 100*F in OK and below 20*F. I'd say the majority of my fishing will be spring & fall though so I'm concerned the 25w40 wouldn't provide good enough startup protection in cold weather and 10w30 wouldn't provide enough hot weather protection at high RPM's...on my 4.3L inboard boat I'm running 15w40 Rotella but this Merc is my first outboard boat and I want to do it right.

So any input I can get would be helpful.

 

[Alumarine]

If it's a newer 50hp the manual recommends 10W30 for your application.
Good for over 100 and below 0.

 

[USA_boater]

If it's a newer 50hp the manual recommends 10W30 for your application.
Good for over 100 and below 0.

It is 2019 model, but I thought 100*F was the cutoff for 10w30...There is a sticker under the motor cover that shows a chart I need to look at again when I am home. But you sound pretty confident that it should be 10w30.

 

[Alumarine]

The manual says 10W30 is good for ALL temperatures.
And it should be FC-W certified.

 

[USA_boater]

Went to a dealer today...they said Mercury (also Quicksilver) is working on a syn-blend 10w30 but at this time they only make it in conventional. However, he said in Oklahoma they always put in 25w40 when they service them. I see they DO make a syn-blend 25w40 which "should" have better cold-flow properties vs conventional in the same weight. So that makes me lean toward the 25w40 QS syn-blend...I lifted the cover on a new Merc at the dealer and it had the same sticker..the sticker indicated BOTH 10w30 and 25w40 were acceptable for all temps...I wonder why they'd treat them the same on that sticker??? I'd imagine my fishing will mainly be between 40*- 85* so I'm not sure what to think...syn-blend 10w30 is what I want but they don't make it in their oil...I could probably find another brand that is FC-W AND 10w30 syn or syn-blend? Honestly I'd like to be able to buy the oil locally though. Does any of this change your mind? what about 25w40 syn-blend in place of the conventional 10w30?

 

[roscoe]

Worrying too much.

Motor is water cooled and has a thermostat.

The recommended oil covers the range is temps.

 

[jimmbo]

Mercury says the 10W - 30 is usable up to 100 degrees ambient air temp in their outboards, they do tend to recommend the 25W-40 oils for their I/Os

They also rate the 10W-30 as good, the 25W-40 as good, and the Synthetic Blend 25W-40 as best

 

[USA_boater]

Well it is the high-rpm's that get me...10w30 at 6k rpms has GOT to shear down to 20wt oil pretty fast no? I am thinking the cold-flow properties of the syn-blend 25w40 will make it better than the conventional 25w40 which the manual says not to use below 40*F...I would imagine I'll be out below 40*F on rare occasion but the majority of use will be above 40*F so I'm leaning towards the 25w40 because of the RPM thing. And oddly enough the dealer I bought it from told me they put 10w30 in it because they are shipped dry. Then told me if I planned to use in colder weather make sure to switch from 10w30 to 25w40 LOL! (their 3nd string mechanic told me that, the guy who got the boat ready for delivery for me)

But the other dealer I was looking at but didn't buy from, had one guy tell me they all come from the factory pre-filled with 10w30 and another guy said pre-filled with 25w40 (both parts/service guys). Very sad

 

[MTboatguy]

Engines are normally shipped dry and I always use the factory recommended weight range in my engines, mercury is giving you two different ranges you can use, so pick one and use it, change it as per their instructions and enjoy your new boat and engine.

I have never purchased a new engine that came filled with oil, unless it was a floor model, if it is in the crate it is normally dry and the dealer gave me the oil with the purchase.

 

[USA_boater]

Well that is how my new lawn tractor was; oil included for me to add when I bought it new. You are probably right; why are people so incompetent? Two dealers selling Merc/Tracker and both service departments clueless...very scary but the norm in today's world. Same people fixing your airplanes too!

I decided that I'll run the 25w40 syn-blend since there currently is not a synthetic option for their 10w30...thanks for your perspective.

 

[MTboatguy]

Fortunately we all have the ability to read the recommendations that the factory give us for the motors they make as well as make the best choice for our particular set of circumstances.

Have fun with that new set up.

 

[jimmbo]

I decided that I'll run the 25w40 syn-blend since there currently is not a synthetic option for their 10w30...thanks for your perspective.

That is a very good oil, but as stated in the owners manual, the 10W-30 is good up to 100F ambient. I would prefer having a thinner oil that can fill up all the clearances quickly when the engine is cold. But it is your engine. The outboard doesn't run as hot as an auto engine does, and the oil sump does get some cooling from water passing thru the midsection so it doesn't get too hot and too thin. However it is your engine and your choice. Volvo 10W-40 is a full synthetic and may be a choice for you

 

[USA_boater]

Funny you mention the Volvo oil...I have a VP 4.3GL in my other boat and was trying to figure out what to run since Volvo discontinued their 30wt syn which was the recommended oil for that boat in 2004. I saw their may have been a bulletin where Volvo changed to recommending 10w40 but I wasn't for sure? Can you confirm this since you mentioned the Volvo 10w40?

I had to make a quick decision so I put in Rotella T5 syn-blend 15w40 but have since bought a jug of Mobil-1 15w50...that boat will never be run in cold weather so I opted for the thicker oil...But part of me wondered if the 10w40 would have been the better choice? The high-RPM thing just gets me...I am almost inclined to just go back to a straight 30wt or 40wt since the boat is used in only the summer. Can you comment on the inboard/outboard oil too?

The merc is under warranty so I'll definitely be using FW-C oil in it but the other boat I like to just be able to buy the oil at walmart. As for 10w30 in the merc 50hp, I don't like that they don't make it in synthetic...do you know if I use an oil weight other than 25w40 or 10w30 (such as 10w40) if they will still warranty it as long as it is a true marine-grade oil?

 

[GA_Boater]

do you know if I use an oil weight other than 25w40 or 10w30 (such as 10w40) if they will still warranty it as long as it is a true marine-grade oil?

That is a question for the people that process claims - Mercury. No user or dealer can answer, they just make the warranty claim and a guy sitting at a desk in Fond Du Lac makes the decision and he may change his mind later on.

 

[jimmbo]

There are a few dozen FC-W certified oils being marketed. I posted the list a couple of times last week. I will assume Wallyworld sells a couple of them. I will try to locate it within the hour and add it here

Edit: to add FCW oil list

FB-00210R Outboard 500 4T SAE 10W-30 YACCO SAS

FB-00211R Outboard 500 4T SAE 25W-40 YACCO SAS

FB-00511J Yamalube Marine Performance FC-W 10W-30 Yamaha Motor Corporation, U.S.A.

FB-00512J Yamalube Marine Performance 4M FC-W 20W-40 Yamaha Motor Corporation, U.S.A.

FB-00604J West Marine Premium 4-Cycle Outboard Oil 10W-40
West Marine Products, Inc.

FB-00616J Lubrax Nautica Tecno SAE 25W-40
Petrobras Distribuidora S.A.

FB-00620K Yamalube 5W-30 Full Syn Marine FC-W
Yamaha Motor Corporation, U.S.A.

FB-00624L 25W-50 Semi-Synthetic Blend
Sierra International LLC

FB-00625L 10W-40 Semi-Synthetic
Sierra International LLC

FB-00626M Power R 4T Outboard
PTT Public Company Limited

FB-00627N MotoMaster Formula 1 Synthetic Marine 10W-30 Outboard Engine Oil
CITGO Petroleum Corporation

FB-00628N Mystik JT-4 Synthetic Blend 4-Cycle 25W-50 Marine Engine Oil
CITGO Petroleum Corporation

FB-00629N Mystik JT-4 Synthetic 4-Cycle 10W-40 Marine Engine Oil
CITGO Petroleum Corporation

FB-00630N Mystik JT-4 Synthetic Blend 4-Cycle 25W-40 Marine Engine Oil
CITGO Petroleum Corporation

FB-00631N Mystik JT-4 Synthetic 4-Cycle 10W-30 Marine Engine Oil
CITGO Petroleum Corporation

FB-00640P Quicksilver High Performance 25W-50
Mercury Marine

FB-00641P Mercury High Performance 25W-50
Mercury Marine

FB-12457P Wave Rider S Outboard 10W-40
Bahrain Petroleum Company

FB-13092U Repsol Nautico Gasoline Board 4T 10W-40
Repsol Lubricantes Y Especialidades S.A.

FB-13103U INA Outboard 4T SAE 10W-30
INA MAZIVA Ltd.

FB-13721U MARINE 4 TEMPS FC-W 10W-30
Minerva Oil SAS

FB-13724U ECSTAR V7000 Semi-Synthetic Marine Engine Oil
Suzuki Motor Corporation

FB-13800W MOTUL Marine Tech 4T 25W-40
MOTUL S.A
.
FB-13827W Marine Inboard Four-Stroke Oil 25W-40
Penrite Oil Company

FB-13852W Suzuki Marine 4-Stroke Engine Oil 10W-40
MOTUL S.A.

FB-14307W Marine Performance 20W-40
Yamaha Motor Canada Ltd.

FB-14800W MOTUL Outboard Tech 4T 10W-40
MOTUL S.A.

FB-20071R Outboard 4000RS 25W-40
IPONE

FB-20114N Evinrude Johnson Marine Stern Drive 25W-40 Oil
BRP U.S. Inc.

FB-20123R KATANA JET 10W-40
IPONE

FB-20208M Avia Outboard 4T 10W-40
Avia France

FB-20215R Outboard 500 4T SAE 10W-40
YACCO SAS

FB-20230R JET 4000RS 10W-40
IPONE

FB-20240R Outboard 4000RS 10W-40
IPONE

FB-20333H IGOL Prosurf 4T FC-W SAE 10W-40
IGOL France

FB-20444H IGOL Prosurf 4T FC-W SAE 10W-30
IGOL France

FB-20555H IGOL Prosurf 4T FC-W SAE 25W-40
IGOL France

FB-20601L Titan Marine FC-W
Fuchs Petrolub SE

FB-21004J 10W-30 4-Stroke Outboard
Sierra International LLC

FB-21005K 10W-30 Synthetic 4-Stroke Outboard & Stern Drive
Sierra International LLC

FB-30220H SUPRA 4
Eduardono S.A.

FB-31001B Tohatsu Premium Four-Stroke Oil
Tohatsu America Corporation

FB-37565U KPO Jet Ski Watercraft 10W-40 4-Stroke Oil
Kawasaki Motors Corp. USA

FB-38003W MOTUL Outboard Tech 4T 10W-30
MOTUL S.A.

FB-38525W Suzuki Marine 4-Stroke Engine Oil 10W-30
MOTUL S.A.

FB-39045W CEPSA Outboard 4T
CEPSA Comercial Petroleo SAU

FB-40003A RAVENOL Outboardoel 4T
Ravensberger Schmierstoffvertrieb GmbH

FB-42111T Liqui Moly Marine 4T Motor Oil SAE 10W-30
Liqui Moly GmbH

FB-42112T Liqui Moly Marine 4T Motor Oil SAE 25W-40
Liqui Moly GmbH

FB-43069W Marine Full Synthetic 5W-30
Yamaha Motor Canada Ltd.

FB-43072W Marine Performance 10W-30
Yamaha Motor Canada Ltd.

FB-44201N Power Boat 4 (SAE 10W-40)
Comercial Importadora, S.A. de C.V.

FB-44215K 25W-40 4-Stroke Stern Drive
Sierra International LLC

FB-44216K 25W-40 4-Stroke Inboard & Stern Drive
Sierra International LLC

FB-44221R Power Rider 4T
Comercial Importadora, S.A. de C.V.

FB-44228J Honda Marine 10W-30 Engine Oil
Idemitsu Lubricants America Corporation

FB-44303J Gulf Pride 4004 - SAE 10W-40
Gulf Oil International

FB-44404M MPM Marine FC-W Engine Oil 4-Stroke Outboard EHP 10W-40
MPM International Oil Company B.V.

FB-80114J West Marine Premium 4-Cycle Outboard Oil 10W-30
West Marine Products, Inc.

FB-80116J West Marine Premium 4-Cycle Outboard Oil 25W-40
West Marine Products, Inc.

FB-80460T Yamalube Marine Performance FC-W 10W-30
Yamaha Motor Distribution Latin America Inc.

FB-80812K RAVENOL Outboardoel 4T SAE 25W-40
Ravensberger Schmierstoffvertrieb GmbH

FB-80813K RAVENOL MARINE OIL PETROL SAE 25W-40 Mineral
Ravensberger Schmierstoffvertrieb GmbH

FB-80814K Nautic 4T SAE 10W-30
Comercial Roshfrans, S.A. de C.V.

FB-80815K Nautic 4T SAE 25W-40
Comercial Roshfrans, S.A. de C.V.

FB-83138K RAVENOL Outboardoel 4T SAE 15W-40
Ravensberger Schmierstoffvertrieb GmbH

FB-83139K RAVENOL Outboardoel 4T SAE 10W-40
Ravensberger Schmierstoffvertrieb GmbH

FB-83140K RAVENOL Outboardoel 4T SAE 10W-30
Ravensberger Schmierstoffvertrieb GmbH

FB-83180R Suzuki Synthetic Blend Marine 4-Cycle Engine Oil SAE 10W-40
CITGO Petroleum Corporation

FB-84000K CEPSA Fuera Borda 4T
CEPSA Comercial Petroleo, S.A.U.

FB-85003K Quicksilver Synthetic Verado 4-Stroke Outboard Oil 25W-50
Brunswick Marine in EMEA

 

[USA_boater]

Thanks to both of you; I spoke to the service manager on the phone from the dealer who I bought my boat from and he said that his interpretation of the language in the Mercury manual was that Yamalube was the only other acceptable oil to keep within warranty with which I disagree. The manual states that you can use any major brand of the proper marine oil if you do not have any Mercury or Quicksilver oil. I interpret that to mean that Sierra, Yamalube, Mystik, etc. would all meet that definition but GA_boater is probably right that it depends on who gets the claim...my money is that a claim in unlikely unless the motor already had a factory defect...any of the marine 4 stroke oils would "probably" be fine as long as the maintenance was done. I just was hung up on the oil weights because 6k RPM is a lot on a multi-viscosity oil and in the automotive side of things I've seen shear proven by used oil analysis. At least a 15w40 or 10w40 would cover all temp ranges AND provide some extra cushion from shearing. Otherwise Mecury gives you one extreme or the other...thin oil that could shear or thick oil that could not provide a quick enough top-end lube in colder weather...blah!!!

 

[jimmbo]

I'm sure the Merc engineers knew what they were doing when they made the recommendations. They wouldn't recommend an oil if it were not going to do what it needs to do. FC-W oils are certified to meet the needs of marine engines. At high rpms, thin oil can stil get into places faster than thicker oil.

Years ago, some auto engine builders used to build race engines with greater bearing clearances than stock production engines, they claimed less friction. However the greater clearances leaked more oil and even with high volume oil pumps the oil pressure was low, and metal to metal contact would occur. Solution was to use higher Viscosity Oils. This provided oil pressure to be higher. Today's engines have far tighter tolerances and do very well with thinner oils. Bearing Materials are more advanced as well and so are the oils

 

[USA_boater]

well I am prob going to operate in 35* - 85* temp...I do wish they made their 10w30 in a syn-blend...thanks again for all the feedback.

 

[jimmbo]

Put a season or two using the Dinosaurus oil, once the engine is well broke in switch to the Syn or Semi Syn. Syn is too slippery for a good break in

 

[USA_boater]

Suzuki specs 10w40...why wouldn't 10w40 be a good year-round oil in an outboard?