synthetic oil vs conventional oil/opinions for all outboards

I don't have enough experience with 4 stroke outboards to comment on engine oil for them (I do use Mobil - 1 full syn in my vehicles, though). Given my knowledge of cars, however, I very likely would use a full syn in a 4 stroke outboard.

For 2 strokes, if it is TCW-3, it's fine for me. Thus, I usually use Super Tech from Walmart, unless they have Pennzoil on sale cheaper. I have run some Royal Purple full syn (won it in a raffle, no way I would buy a 2 stroke oil that costs that much), and while I did notice a slight decrease in the smoke, no other differences were notable.

As far as gear lube, again, I use whatever is cheapest. Half the time, what I use doesn't even say marine on the bottle. If you notice, even the expensive brand name gear lube is held to the same API GL-5 rating as the cheap stuff. Just about any 80W-90 automotive gear lube is GL-5 rated, as there isn't yet a marine rating for gear lube that I'm aware of. If it has the GL-5 rating, I shop for the best price.

I personally can't see the need to use a full syn. gear lube, or change out a cheaper lube twice a year. The only reason you change out the gear lube annually anyway is because of the likelihood of water intrusion. The reason you change it annually is so you can drain it before the first freeze, seeing how the gearcase can crack if water freezes. Notice how you don't need to change the lube in a manual gearbox in a car all to often. It doesn't break down all that much. All oils are going to repel water, so a minor intrusion shouldn't cause a major issue no matter the lube. If you have a big enough issue that enough water comes in, the type of lube shouldn't matter, seeing as for enough water to cause harm to fit in, the lube has to leave, and is thus left as a film on the top of your favorite lake.

Just my 2 cents worth.

I agree with bassboy.I just buy the Wal-Mart 2 cycle oil.Run 80-90 auto gear lube in my lower.
The only time I run different oil is in my race motor which I run Merc Premium & Luberplate 105 in my lower.

If you have lower unit oil that turns dirty, you have lower unit problems.

Like bassboy said, the only real reason that it has to be changed at all is because of the chance that it might be contaminated with water. Other than that, there should be no contamination other than ordinary gear wear.

There is something about that supertech lube that makes it turn milky for some reason, even without the presence of water. I'm not sure what that's about. I currently have it in the lower unit on my 90 because that's all that I could get my hands on at the time.

i have been running royal purple in my cars and trucks for several years now}trans rear and motor and have noticed a huge improvement in my mileage i switched my lower unit oil t the Royal and it has given me a few more mph I like the fact that it reduces the wear on my equipmenti have been running it in my tundra since the first fluid changes and will never switch back

I have seen several 2 stroke motors, motorcycles, snowmobiles etc, Fried due to amsoil. It is something i will never ever use.. The biggest thing about synthetic oil IMO, is they generally control smoke a whole lot better by there formulation in the 2 stroke applications.. I dont think ill ever run synthetic oil in a 4 stroke, to many vehicles on the road with 250k on them that have been well maintained of good ol motor oil...

I have a 1968 Evinrude Fastwin that has never had the lower unit opened and has never had anything but dino-lube in it. I'm not attempting to knock synthetics but sometimes there are answers to questions that were never asked all in the name of technology. If it ain't broke, there's no reason to fix it, imo.

That milky color that some dino-lubes turn without the presence of water may be nothing but cosmetic.

My Merc. came from the factory with a l/u oil that was dark blue almost like 2 cycle oil. You couldn't tell if that stuff was contaminated or not.

im afraid theres goin be a war break out on here over oil I belive you get what you pay for But there is some cases were its a crock like 50/50 anitfrezze

I run Mobil-1 full syn. in my two cars, and truck. Love it, better gas millage, but only by about 10 miles per tank. I also use 1 Lucas oil in every oil change for the truck, and also 1 lucas oil fuel treatment for every 4th or 5th fuel up in the car. As far as a 2-stroke is concerned a gasket would not of been the cause of an oil leak frying a 2-stroke, cuz you mix the oil in the gas. Unless its oil injected. and no Boater1234 I am not calling you out or trying to argue, just stating a fact.

How can it be "way better" if dino oil does the exact same thing with no problems?

What is better about it? Because it costs more?

If it raises rpm (and you actually need that), okay. If it increases gas mileage, okay. Those are things that would make it "better". Dino lube has been protecting lower units for years with perfectly acceptable protection.. until synthetics came along. Now it is suddenly inferior although it still does 100% of what l/u oil is supposed to do.. lubricate and protect the parts in your l/u.

I have never changed my l/u oil in any motor more often than once a year unless I blew a seal. There is no need for it. Sometimes, it goes longer than that. If you have a leaking seal, it doesn't matter which oil is in your l/u. They will still both do what they are supposed to do and neither will stop your l/u housing from potentially cracking during a freeze.

I use the cheapest I can find in my 2 stroke, after all.... I am burning it. In the lower unit I just used the recommended from the marine shop and change it once a year. Worked great in my Merc, and we will see how this Chrysler holds up.

boater1234 said:

If u want to go cheap go with the pensoil synthetic they sell it at walmart for around $25.00 a gallon and it will last a long while.Funny i talked to the manager at walmart the other day as we got into a conversatin about oil as i was looking.He asked me what kind of oil i wanted i said the castrol edge and he said u want to here a funny thing,i said ok whats up,so he said the walmart super tech brands[all of it]is just pensoil rewrapped how about that one for u.He said he knows this for a fact and has been this way for years,crazy huh.Even walmarts super tech synthetic oils are pensoil just cheaper because of the name.Kind of like a 20hp merc or a 20hp tohatsu rewrapped with different decals.

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I buy the little grey 16oz. bottles of the super tech. I use a 50:1 mix in 6 gallon cans. Makes it easy, one bottle for one tank. I use my boat on electric only lakes as much as I use it anywhere so I rarely use the outboard.

Because the guy stocking the shelf at Wal Mart is actually a chemist and knows the differences between Pennzoil and Supertech and secretly watched this happen at the refinery? :lol:

Guy, don't believe everything that you hear without doing a bit of research first. They may come from the same refinery (maybe, Wal Mart contracts their oils to the lowest bidder) but that does not mean in any way, shape, form or fashion that they are the same oil with two different lables on it. They have their own formulation to meet whatever spec suits them and bring their price point in at the bottom of the barrel. This is where it currently comes from: https://www.warrendistribution.com/

This myth has been debunked hundreds of times on the internet on various boat and automotive forums by guys a lot smarter than me that formulate oil and work at those companies.

Does it work? Most likely. Is it as good as the name brand stuff? Maybe, maybe not. Can you tell who made it from one year to the next? Only if you go digging.