using automotive oil for a 4.3 stern drive

[garycinn]

Re: using automotive oil for a 4.3 stern drive

Originally posted by BillP:<br />Merc's web site only lists a 2 stroke synthetic blend oil. There isn't a 4 stroke synthetic crankcase oil listed. Is it missing from their web site?

I don't see their 4-stroke syn blend on the web, but it is advertised in national magazines.

 

[TheOilDoc]

Re: using automotive oil for a 4.3 stern drive

Engine oil service categories do not drive engine technologies. Engine technologies drive changes in oil service categories.<br /><br />The latest API SL category was established to represent the entire gasoline engine industry. I am not aware of technological engine advancements in the Marine Mercruisers that would necessitate a change to the SL oil specification.<br /><br />For gasoline engines, the latest API engine oil category (SL) includes the performance properties of each earlier category (SH). If engine specifications call for an API SH or SJ, an SL oil will provide full protection. It should be noted that Diesel "C" categories do not always work in the same sequencing way. For example a CH-4 will not include a CF-2.<br /><br />I am also not aware of a 25W-40 synthetic Mercury oil. The synthetic oil mentioned may be in reference to Mercury's four stroke outboards.

 

[LubeDude]

Re: using automotive oil for a 4.3 stern drive

This is indeed intertaining to see TheOilDoc going through what I have for the last year.<br /><br />Have at it Doc.

 

[garycinn]

Re: using automotive oil for a 4.3 stern drive

Here is the aussie Merc site that talks of both oils -- outboard and sterndrive.<br /><br /> http://www.mercuryverado.com.au/MPI/MMWebSite.nsf/0/23337471B1F5AEBBCA256E9900142D25?OpenDocument

 

[Scaaty]

Re: using automotive oil for a 4.3 stern drive

What the Harley heck...my 72 Sportster dragbike uses 20-50 Castrol, my 79 FXS chopper uses 20-50 Castrol, and my Big Red EVO first year (84) Bagger uses 20-50 Castrol....zero oil problems......and that makes the newest at 20 years old already!<br />Ps. And today fresh Havoline 10-30 in the new Honda pressure washer, and the 1978 Honda Mini-trail got Valvoline straight 30....riding and push mowers next, and the Astro will get it this week too....I think the boats are done, and down to one more bike...WAIT...chain saws, weed wacker, blowers, generator..........AGGHHHH!

 

[NYMINUTE]

Re: using automotive oil for a 4.3 stern drive

I hope the "boys" @ OPEC can't hit this topic. The little varmits will raise crude to $100. a barrel.

 

[TheOilDoc]

Re: using automotive oil for a 4.3 stern drive

Member garycinn:<br /><br />A Mercruiser synthetic 25W-40 is not yet available in the U.S.A. You may see it soon.

 

[LubeDude]

Re: using automotive oil for a 4.3 stern drive

I wonder why with the average I/O running about 140 degrees, they would reccomend a 40 weight?<br />I think after thinking about it for a bit, I can somewhat answer my own question. Probably due to the fuel delution issue so it wont thin out to much before changes. I have to admit, that it surprises me as to the amount of fuel delution in a boat engine.

 

[summit1]

Re: using automotive oil for a 4.3 stern drive

So, what is the conclusion? Stick to merc oil?

 

[tommays]

Re: using automotive oil for a 4.3 stern drive

you will never get a conclusion you have to read whats here and make you own pick<br /><br />for my self i use a 30 wt oil that meets merc spec and am happy <br /><br />there are other people who use and oil that does not meet merc spec and are happy<br /><br />tommays

 

[TheOilDoc]

Re: using automotive oil for a 4.3 stern drive

Originally posted by LubeDude:<br /> I wonder why with the average I/O running about 140 degrees, they would reccomend a 40 weight?<br />

With the exception of the 25W-40, Mercruiser has determined that at ambient temperatures above 50'F, 40 weight will provide optimal operating performance while still maintaining good start-up and cold idle protection. Coolant temperature is not a good indication of cylinder temperature and/or oil temperature. It is not uncommon for oil temperatures to exceed coolant temperatures.<br /><br />There is a direct correlation between an oil's viscosity and its shear and wear properties. Higher viscosity oils generally exhibit higher shear and wear strength. <br /><br />There is also a correlation between temperature and oil viscosity. Higher temperatures reduce viscosity. Lower ambient temperatures and lower cylinder operating temperatures (not necessarily coolant temperatures) cause the oil to become more resistant to flow. Again, a correlation can be drawn between oil’s resistance to flow and its inability to lubricate properly. <br /><br />The object is to maximize shear and wear strength at higher oil temperatures using a higher viscosity, while minimizing the oil's high resistance to flow at cold temperatures by using a lower viscosity. This is why we see multi-viscosity oils. They provide good protection at cold start ups and good protection under high operating temperatures.<br /><br />The problem for marine engines is that most multi-viscosity oils have added viscosity improvers and polymers that make them multi-viscosity. By stretching out the abilities (viscosity) of the oil, the oil is more susceptible to shear breakdown. This may not be an important factor in an automobile engine. Marine engines see much greater loads and stresses on the oil.<br /><br />Straight weight oils will not have these viscosity improvers. This makes them less susceptible to shear breakdown when under high loads, but they will have less flexibility for temperature differences. This is why Mercruiser recommends different straight grade viscosities for different ambient temperatures. Maximum protection for a given temperature. This is also why they recommend their unique 25W-40. An all-temperature multi-viscosity oil without viscosity improving polymers.

 

[butlp]

Re: using automotive oil for a 4.3 stern drive

Wow! TheOilDoc sure is a breath of fresh air on the oil debate! Such concise detail and yet in layman terms. I have a feeling you and Forktail will get along just great!

 

[summit1]

Re: using automotive oil for a 4.3 stern drive

Tom-<br />Have you torn down one of your motors after using it for a while with 30 wt oil?<br /><br />I use my boat 95% of the time pulling skiers and wakeboarders...it is harder on a motor to have to hole-n-go and stop and go, etc. I have been running rotella (a certified merc mechanic recommended it, believe it or not). I am in TX, a little bit hotter weather. Would I be better off just using straight 40 wt oil?

 

[LubeDude]

Re: using automotive oil for a 4.3 stern drive

Reguardless, Id use the Rotella. I believe the only straight weight oil you will find will be a racing oil, and they do not have the additive package the merc or the diesel oils have.

 

[summit1]

Re: using automotive oil for a 4.3 stern drive

Thanks LubeDude. Does Rotella have anything other than 15w-40? This is what I have been using. <br /><br />I am curious to what some of you guys have found if you have torn down into your motor after using something other than merc oil...was there a lot of wear, etc or did the oil look like it protected well?

 

[tommays]

Re: using automotive oil for a 4.3 stern drive

summit<br />my bother in law have boated together for the last 32 years mostly hard core watersking barefoot,salom,jumping the whole 9 yards so i think were pretty hard on are boats<br /><br />currently i have a 1995 3.0 which we use as the beach and to cruise there is no need to take apart because it runs as good as new<br /><br />we ski with a 1977 correct craft with a 5.7 the orginal motor in that boat lasted until the end of the 2003 season the only work done was one set of manifolds and elbows and the spring plate on the flywheel to drive the velvet drive trans has gone 2 times<br /><br /><br />we do take very good care of are boats and the 5.7 could was not dead in 2003 but had finaly rusted so much you could not remove the heads with out breaking the motor<br /><br />my brother runs a chevy dealer so it became a no brainer to just by a new motor <br /><br />we have allways just used good 30 WT and never had a problem i would think in texas its a lot hotter so you need to conisider that but i think a motor lasting about 25 seasons of hard use speaks for it self<br /><br />tommays

 

[LubeDude]

Re: using automotive oil for a 4.3 stern drive

This is not boat related, but it shows corrosion aspects.<br /><br />A few years ago, I towed a 66 Elcamino out of a field, (Yes, its the one in the pictures in the other post). It had a 283 in it that had not been run for about ten years. The car had been out in the weather sitting flat on the ground with no tires or air cleaner. I rebuilt this engine with all the stock parts except gaskets rings and bearings. When I tore it down, there was "NO" rust inside the engine at all. Im telling this story to say that the corrosion,(rust) protection issue Probably isnt much of an issue if storing in the off season for just a few months.<br /><br />Even though the Mercury oil appears to be a very good oil, I see "NO" reason you couldnt use automotive oil as long as you service your engine regularly and at recomended intervals.<br /><br />This obviously isnt a scientific approch and should be taken as just an opinion. Personally I would use the Amsoil 15W-40 Diesel Marine synthetic if I had an outdrive engine, or at least Dello 400 15W-40.<br /><br />Oil, Buy it, use it, Its hard to go wrong. I seriously doubt that even if you bought WallMart Supertech 30W you would ever suffer any problems,)Although I wouldnt), but Im anal a bit on lubtication so I try and use the best I can afford.

 

[summit1]

Re: using automotive oil for a 4.3 stern drive

 

[summit1]

Re: using automotive oil for a 4.3 stern drive

Thanks for all of the help guys. I appreciate the info.

 

[TheOilDoc]

Re: using automotive oil for a 4.3 stern drive

There are a large variety of brands and viscosities available for the Mercruiser.<br /><br />Wal-Mart's SuperTech Universal 30W meets the requirements of the Mercruiser. It has the right viscosity. It is not a polymer containing multi-viscosity. It is not a synthetic. It carries the CF, CF-2/SJ API license and certification.<br /><br />Four reasons not to use Amsoil 15W-40 in your Mercruiser:<br /><br />1. Wrong viscosity. Only viscosities of 20W, 30W, 40W, 20W-40, 20W-50, or 25W-40 are recommended.<br /> <br />2. It is synthetic. Mercruiser recommends not using synthetic oils. There could be a host of reasons why (incompatibility with parts, solid additives, etc.).<br /><br />3. The oil is not licensed and certified, or even listed by the API to carry the CF, CF-2/SH (or latest SL) category.<br /><br />4. It is a multi-viscosity oil. Mercruiser recommends against using a multi-viscosity oil unless it is a quality 25W-40, 20W-40, or 20W-50.<br /><br /><br />Three reasons not to use the Delo 400 15W-40:<br /><br />1. Wrong viscosity. Only viscosities of 20W, 30W, 40W, 20W-40, 20W-50, or 25W-40 are recommended.<br /><br />2. Wrong API rating. It is not a CF, CF-2/SH (or latest SL) rated oil.<br /><br />3. It is a multi-viscosity oil. Mercruiser recommends against using a multi-viscosity oil unless it is a quality 25W-40, 20W-40, or 20W-50.<br /><br />When trying to maximize engine life, it does not seem reasonable to go against the recommendations of the engine manufacturer. There are many proper oils available. The Wal-Mart oil is one of them.