Marine versus Automotive

[NDcarper]

For freshwater use, is there any great advantage using Marine designated motor oil in a small 6hp outbaord? Would Syntec, Mobil 1, or Rotella Synthetic work just as well.
With regard to mineral oils, would automotive Rotella 15-45 work just as well?

 

[NDcarper]

This is for a 4 stroke engine.

 

[Dagwood]

If this is a 2-cycle outboard where oil is mixed with the gas...then you need to use the proper 2cycle oil in the gas as specified in your manual. I prefer to use Pennzoil marine 2-cycle oil in mine. I believe it is a semi-synthetic 2 cycle oil.

If it is a 4 cycle

Check out your owners manual. The requirements are usually something like "CG-SJ4". Rotella does meet that designation and could probably be used. (I assume you meant Rotella 15w-40)
I am not sure that Mobil 1 is available in 15w-40. I suppose you could use 15w-50, however I do not believe it carries the correct rating.

 

[Dagwood]

OK...I apologize...you did say it was a 4 cycle.

 

[NDcarper]

So basically a a CG rated dessil oil and SJ automtive rating.
Pennzoil Marine is $2 a quart while Rotella T is $2.38.No savings going with the Rotella.

As far as synthetics
Mobil 1 makes a 20-50 that is hard to find. Syntec makes a 15-50, and Rotella synthetic is 5-40.

I am elaning to a synthetin once the break=in period is complete.

 

[Dagwood]

Synthetic is a good choice for an engine that sits most of the time. Marine engines also run longer at high rpm and need all the protection you can give them. That's my opinion.

 

[Brett Miller]

Amsoil has an oil specifically for 4 stroke outboard engines.

 

[NDcarper]

Is ther AMSOIL marine synthetic orth teh extra cost?

 

[dwendt44]

Marine engines Run cooler(140-160º) than auto engines and tend to stay reved up longer at a time. Also may sit without running for extended periods.
So thinner syn oil would work as well as Rotella, etc..
Marine oil has more anti-corrosion adds.,

 

[LarryL]

Boat engines do have a harder life. In a car, going down the freeway you need very little gas to keep going and if you let off the gas you coast. In a boat you need a lot of gas to keep going and if you let off the gas you stop. Also boat engines live in a tough environment, are over-cooled and spend a lot of time idle. It is often times difficult to change the oil, that is get to it, get all of it and dispose it. I had a 40' sail boat, used synthetic oil and had double Frantz oil filters. I used a uoa to determine the best oci and bypass filter change interval. With an outboard I would run synthetic and change it frequently. I would justify an oil analysis by saying it's a learning experience for me, not just for the motor. Sometimes you lean best when you figure out things for yourself.

 

[Mike_dup1]

quote:

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Is ther AMSOIL marine synthetic orth teh extra cost?

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What is more important, saving a few $$ or protecting the engine with a good lubricant.

The Amsoil is NMMA certified.

 

[cavitating]

I have a Yamaha F8, four stroke, twin cylinder outboard and it calls for 10W30 oil. I have been using Mobil 1, 10W30 without problems. The engine has no filter so I change the oil every 20 to 25 hours. It uses less than a quart of oil and it takes about 5 minutes to do the oil change.

 

[friendly_jacek]

Viscosity is only one issue.
Certification is another.
Boat engines often call for old API specs like CF-2/CH-4/SJ (in my 2003 3.0L Merc) to make sure owner is using shear-stable oil loaded with ZDDP.
Current SM oils have only a third of ZDDP of the old oils. Good luck with your Syntec or Mobil 1.

 

[XS650]

quote:

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Originally posted by friendly_jacek:
Viscosity is only one issue.
Certification is another.
Boat engines often call for old API specs like CF-2/CH-4/SJ (in my 2003 3.0L Merc) to make sure owner is using shear-stable oil loaded with ZDDP.
Current SM oils have only a third of ZDDP of the old oils. Good luck with your Syntec or Mobil 1.

---

Correct me if I'm wrong, but I don't believe that those specs require any ZDDP.

 

[friendly_jacek]

No, but different specs had different levels of limits of P. For example: SG no limit, SH 1200ppm limit, SJ 1000ppm limit, and finally CX-4/SX no limit (except for the upcoming CJ-4 with 1200ppm limit).
The oils were traditionally formulated with P near the limit due to cheap ZDDP.
I hope this clarifies for you.

 

[dwendt44]

Marine engines don't have a cat. converter to worry about, so they can use adds that would/are not allowed in automobile.

 

[TooSlick]

You'll be changing the oil in this motor once a season and I can't imagine a 6 Hp engine holds very much oil? I'd use the Amsoil 10w-30, Four Stroke marine or a diesel formulated synthetic like Delvac 1, 5w-40.

I just don't see any savings by using a cheap oil in this case....

TS

 

[Geoff]

Mercruiser, famous 25w-40 guys, spec 10w-30 for their 4 stroke outboards. Not sure how the lube system works in the 6 hp, but the thinner stuff might make more sense with such a small motor. I would go with the Mercruiser or HDEO 10w-30 (Rotella, Delo) to get the anti-corrosion additives.

 

[NDcarper]

OK
well I'm just gonna use Pennzoil Marine 15w40. Its $2 a quart and if I change it once a month thats $4 a season. The engine only takes half a quart. A friend of mine told me of an interesting article showing automotive oils do not contain sufficient quantities of corrosion inhibitors. The least expensive marine oil blows the others away as far as corrosion resistance. Pennzoil automotive suprisingly is the only one that barely qualifies for corrosion resistance. Suprisingly it cost more than the marine they make.

 

[TooSlick]

You forgot to mention that summer in ND is only two weeks long!

Better get out there, times a wastin'

If you're storing the engine 90% of the time it probably doesn't matter what you use. I would make sure to use a fogging spray before you put it away for the ten months of winter.

TS