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Author Topic:   Synthetic Oil in 4-stroke Outboard Engines
Cole posted 02-27-2004 09:56 PM ET (US)   Profile for Cole   Send Email to Cole  
[Is there a benefit to using full-synthetic oil in the lubricating oil sump of current 4-stroke outboard engines as made by Yamaha, Mercury, Honda, Suzuki, and others?]

I would have to think that it couldn't hurt, and it just might be better [than the recommeded oils]. I don't know in a marine application such as a 4-stroke outboard [if my supposition that synthetic would be better than the recommend manufacturer's oil would be valid]. I run Mobil-1 in all my cars. Is there any reason to not do the same with my new F200?

At the moment I'm planning on leaving the standard stuff in for the break-in and then switching to synthetic.

jimh posted 02-27-2004 10:50 PM ET (US)     Profile for jimh  Send Email to jimh     
Considering the price of a new outboard, I would follow the recommendations of the manufacturer for all lubricants. If they thought Mobil-1 was the way to go I am sure they'd specify it in their manual.

The viscosity and grade of the oil specified for these marine applications is often not available in automotive products. The new Mercury 4-stroke requires NMMA Certified FCW SAE 25W-40 oil. Can you get this in a Mobil-1 brand package?

Perry posted 02-28-2004 12:59 AM ET (US)     Profile for Perry  Send Email to Perry     
My Honda manual says to use 10W-30 viscosity for general use but other viscosities may be used in hotter or colder regions.

Honda recommends API service category with the "starburst" certification mark displayed on the container.

I have been using Mobil 1 in my vehicles and 4 stroke outboards for years with nothing but great results.

JBCornwell posted 02-28-2004 08:55 AM ET (US)     Profile for JBCornwell  Send Email to JBCornwell     
I use Mobil1 in my vehicles and in my Suzuki DF70, Cole.

The notion that it might be inferior to petro-lubes (except for break-in) never occurred to me, and still doesn't.

I did use the oil supplied by my dealer for break in on the theory that a "too-good" lubricant might retard seating of rings, etc.

Quite a few Yamaha and Mercury 4 strokes experienced gas-in-oil syndrome, partially from incomplete seating of rings on break-in and partially from running too cool (read rich). One might speculate that use of superior, fully synthetic, lubricants during break-in could have been a contributor.

Mercedes Benz insists that I use Mobil 1 in my ML. I insist on it in my Suzuki.

Red sky at night. . .

jimh posted 02-28-2004 09:26 AM ET (US)     Profile for jimh  Send Email to jimh     
JB--That is an excellent point (that use of a synthetic oil during break-in might affect engine wear-in of rings)!

If you used a full synthetic oil like Mobil-1, would you modify the oil change interval to a longer period?

Cole posted 02-28-2004 10:12 AM ET (US)     Profile for Cole  Send Email to Cole     
Thanks guys for the input-

Point of clarification…I would not be changing the recommended viscosity…just simply going from a dino-oil to a full synthetic. The Yami manual does give a range of recommended viscosity’s but that is dependant on the environment in which you will be using the motor (similar to what you see in your cars manual).

As for break-in that’s just my $.02 in that with countless cars it has been recommended to me to not use full synthetic during break-in in order to allow all the internals to seat properly. Now there are a few cars such as the Z06 (and a few Porsche’s I believe) that come straight from the factory with Mobil 1…so maybe that’s not true.

Either way…if I was to stick with a recommended viscosity…I can’t see (yet) any disadvantages to the synthetic

Cole posted 02-28-2004 06:30 PM ET (US)     Profile for Cole  Send Email to Cole     
FYI...just looked it up 10/30 or 10/40 for the 200 Yami 4-stroke
JBCornwell posted 02-28-2004 06:56 PM ET (US)     Profile for JBCornwell  Send Email to JBCornwell     

Mercedes delivered my ML with Mobil1 in it, so they seem to have no concerns about seating rings, etc. during break-in.

The reason they give me for requiring full synthetic oil is the computerized oil condition evaluation that schedules oil changes based on real-time analyses of the oil. In 123,000 miles it has called for a change in as little as 3,000 miles (short trips, city driving) and as long as 13,000 miles of long trips at cruise speeds.

Without that unique sensor in the crankcase and the computer to compute condition, I wouldn't alter the change cycle.

Red sky at night. . .

rbruce posted 02-28-2004 10:01 PM ET (US)     Profile for rbruce  Send Email to rbruce     
I do not think JB's MB has an oil "analyzer" (analyzing oil color for carbon particles suspended, metals in suspension, solvents and coolant, like they do in oil analysis of piston engined airplanes), rather, it has a computer that collects how many driving cycles he does before the engine coolant temperature has reached normal operating conditions among other relevant variables (millage from last oil and filter change, average rpm's, etc.), and perhaps, extrapolating from these data stored, if the car has been driven in short cycles which might or may not be stop and go conditions, which claim a huge toll in oil lubricating quality.

By requiring synthetics and using these "common sense" data, MB insures itself from premature oil break down, excesive drive train wear and therefore short engine life or worse, oil consumption before warranty has expired. In the USA with the magnificent road and highway system the distances driven daily in most cases might exceed 16 miles per cycle (distance between starting and stoping the engine before it reaches operating temperature) and this helps conserve the oil free of combustion byproducts and good filtration will keep carbon and metals from causing excessive friction.

In very cold temperatures the motor might take longer to warm up, this will throw a flag and shorten the oil change interval, in towing conditions the computer might record higher than average coolant temperatures even oil temperatures if it has such an oil temperature sensor and throw in a flag that might also shorten the oil change interval. All else the computer might conclude that the conditions are ideal and increase the oil change and filter interval.

But I believe that in none of the above conditions JB runs his MB's drivetrain at 4,500 rpm to 5,500 rpm under load most of the time, like you might do with your outboard. I am a fan of synthetics in my car as I believe that I am postponing his drivetrain's demise, however, my GMC Jimmy seldomly sees 2,500 rpm even in our mountainous country and I replace the oil and filter and other lubricants at 1/2 the manufacturer's recommendation as an extra meassure of precaution. However, my outboard is almost always used at 4,500 rpms since I have not mastered trolling yet, in very humid conditions, perhaps at temperatures that could promote condensation inside the crankcase, with sulphurous fuels, etc. I would call the latter conditions extra severe.

Therefore, the recommendation of the outboard manufacturer as per the motor oil quality certification and viscosity are crucial unless, you work with the manufacturer and know something that we do not, I would stick with his recommendation.

SuburbanBoy posted 02-29-2004 12:56 PM ET (US)     Profile for SuburbanBoy  Send Email to SuburbanBoy     
The point about outboards running at higher speeds is valid, and they also frequently run at close to peak output (full throttle). If the Mobil 1 meets the standards, it is tough to beat. I have noticed that recently Mobil is marketing specialized oil. For example, they now sell several grades of motorcycle oil. This oil has more additives to extend the life of gear drive systems than their typical automotive oil. One reason for the differences is to limit catalyst contamination. The automotive spec limits certain gear life extending additives because if the engine burns this type of oil(s), they tend to contaminate delicate automotive catalysts. Most motorcycles have no converters, and no damage potential. I would guess that Outboard focused motor oil would also have some unique requirements and as outboards proliferate, the probalility of specialized oil availability is higher.


JBCornwell posted 02-29-2004 06:36 PM ET (US)     Profile for JBCornwell  Send Email to JBCornwell     
I suppose I should clarify for RBruce.

The ML has a sensor in the crankcase that measures oil conductivity in real time.

The firmware that calculates the change interval calculates miles remaining to recommended change based on:

Engine hours.
Vehicle speed.
Coolant temp.
Load signal.
Engine rpm.
Engine oil temp.
Engine oil correction factor (conductivity).
Engine oil level.

My MB Service Training Manual assures me that If I ever need to add oil (not yet in 123,000 miles) the calculated interval will be extended by the change in conductivity sensed on the next running of the engine.

Perhaps my use of the term "analysis" to avoid a 300 word explanation was oversimplification. Nevertheless, I consider measuring conductivity an analysis, as every oil condition factor you mentioned affects oil conductivity.

I see no reason why a similar sensor and program wouldn't be suitable for a 4 stroke outboard.

Red sky at night. . .

Bigshot posted 03-01-2004 02:35 PM ET (US)     Profile for Bigshot  Send Email to Bigshot     
I am not gonna give a sermon here....I use it in my cars, bikes, and boats. NEVER had failure from it yet. MB's warranty is VOID if non-synthetic oils are used.....period. That gets my vote.
Jerry Townsend posted 03-01-2004 04:13 PM ET (US)     Profile for Jerry Townsend  Send Email to Jerry Townsend     
I am totally in favor of Mobil 1 and use it in virtually everything. Used it in a GMC 3/4 ton pickup many years ago - and put around 175,000 on that engine before replacing with a larger engine - the original 350 was almost like new, with very little wear. The replacement was made just for more power.

At the time I purchased the initial pickup ('76) I called GM and asked their thoughts and comments - no problem, no impact on the warranty,

But, as one mentioned, I would recommend breaking in with the manufacturer's break-in oil and then change to Mobil 1.

In the '70's and 80's, some manufacturer's seals would not hold Mobil 1 all that well. I suspect that has changed by today.

Mobil 1 recommended (years ago) to drive the vehicle for 50,000 miles and then change oil and filter. Instead, I would run until I was down a quart (about 6,000 miles) and then change filter and add two quarts of oil. When that engine was changed and inspected, the engine showed virtually no wear - commendable! Today, I am doing the same thing in a Buick LaSabre and another GMC 3/4 ton pickup. ----- Jerry/Idaho

rbruce posted 03-02-2004 10:19 PM ET (US)     Profile for rbruce  Send Email to rbruce     

Thanks for the ample clarification! Indeed the MB has a sophisticated oil analysis system and your MB's millage and no oil consumption show how much of a close tolerance motor your car has!

But how do automotive situations compare to boating situations? Aren't outboards used under load all the time even at part throttle? Are these 4 stroke motors built under the same close tolerance as the automotive motors? Could such a close tolerance motor survive 500 hours under load all the time?

I would like to learn more on these recommendations from the 4-stroke manufacturers...but I would also be interested in learing more on the life cycle of such a 4 stroke motor also.

I do trust Mobil 1. I have used it in most of my cars including my former 250,000 Km Honda Civic, but after performing oil analysis when the car was almost new, the lab recommended changing the oil and filter every 5,000 Km, sample after sample done at 5,000 Km change interval and at $6 per liter it is a matter of blind faith to keep using it. Perhaps my Honda was not built as a MB.

By the way Mobil does recommend using Mobil 1 as soon as possible, even before "break in" is done.

Sal DiMercurio posted 03-02-2004 10:50 PM ET (US)     Profile for Sal DiMercurio  Send Email to Sal DiMercurio     
I'm with Bigshot on this, all the way.
I've spoke of an oil test that would be coming out, well, it's out.
Bass & Walleye Boats magazine has a special artical on 4 stroke outboard oils.
It's going to surprize many of you guys, big time.
One of the weak points of the 4 stroke { according to the artical } is trolling.
It states that when run at troll speeds, fuel delutes the oil in the 4 stroke crank case & it's not a good thing.
Get the March 04 issure, it's "VERY" informative & should put an end to some of the controversy of oils for outboards.
It's written by Bill Grannis, { a very good friend of mine } from whom I get much of my information from.
Cole posted 03-03-2004 02:43 PM ET (US)     Profile for Cole  Send Email to Cole     
Can you give us an overview of the article with its general conclusions. I've gone to the Bass & Walleye Boats magazine site in addition to trying to find a copy here (SoCal) locally but have come up empty handed in terms of being able to find the article.


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