Synthetic Oil

[Cape Codder]

I Have A F50 Yamaha And I Just Did My 10 Hr. Oil Change. I Used 10w-30 Amsoil Synthetic Marine Oil. Also Used Marine Gear Oil For The Lower Unit. Very Expensive Compared To Regular Oil But Its Worth It. Never See Any Discussion On This Site About Synthetic Oil. Anybody Use It?

[Putershark]

Their have been several discussions on it's use, just punch in the words "Synthetic Oil" or "AMSOIL" in the site search tool and you can read several

[Cape Codder]

Thanks Dave.

[MolarBoater]

I use Suzuki products in my Suzuki motor but have to mail order and wouldn't loose too much sleep over different brands of similar oils.

[Cape Codder]

thanks for taking the time to reply.bill

[Cincinnati]

My mechanic told me not to use synthetic oil in my Honda. He said that the regular oil helps prohibit 'making oil'. That is, keeps the piston rings seated so that there isn't fuel blow-by into the crankcase. He says that synthetic lubricates too well and allows fuel mix into the crankcase oil. Either way, you can't go wrong with using regular oil changed every 100 hours or less.

[Cape Codder]

some say o.k. others say no way. nothings ever easy. thanks for taking the time to reply to me.bill

syn.oil for cars ok, boats no. moisture is a problem reg oil absorbs some no problem. syn does not. moisture will cause crankcase acid build up in 4 strokes.

[Cape Codder]

In Yesterdays Mail I Received A Brochure From Yamaha Suggesting I Use Yamalube 4-m. In The Brochure It States Its Properties Are Basically Synthetic. The Price Is More Than Twice That Of Fossil Oil But Less Than Amsoil. I Will Be Using Yamalube In My Yamaha For All The Warranty Issues. This Is My First 4 Stroke And Research From You All Has Been Very Helpful To Me. Thanks For Your Reply.bill

[Putershark]

There is only one “sure” way to remove moisture from the oil (no matter which type) and that is through the application of heat to the oil. That is why it is critical that your engine thermostats work as designed, and that you run the engine both long and hard enough to "boil off" that moisture before engine shut down, this no matter what is in the crankcase…

We have to understand though the end game in certain people telling you one thing or another when it comes to engine care. Some mechanics (I'm being kind here) are sly and realize that don't get paid as much to change your oil as they would installing a new power head AND (worse yet) will get paid even more labor dollars to install that power head AFTER the warranty has expired so keep that in the back of your mind when hearing recommendations for sure.

The Outboard makers though do know what can happen when oils that do not contain the correct additives (automotive use grades) for the intended marine environment can do to your engine. That is why the recent push to produce oils that have such additives by the OEM’s. There can be though a large difference though in thermal breakdown and lubricity properties and (even more important) deposit levels left behind between the two oil types be it either a 2 or 4 stroke engine. Now if you plan on keeping your engine for a long time, (or for the re-sale value if you do not) then the use of Marine Grade Synthetic oils is a logical route...

Oil (shocking as it may sound) does not wear out, but becomes diluted with fuel, dirt, and deposits over time and it is during that time period (between your oil changes) is where you need to "choose" just how much engine wear you are willing to have occur on your engine? Like the old FRAM ads use to say "You can pay a little now or a lot latter" still holds true

25 years ago I worked on huge engines that rarely had oil changes (just additions) then again, how many engines do you run now that have lube oil pre-lube pumps installed (oil pressure to 30 plus PSI before it was even turned over) and purifiers that sent the oil through a centrifuge to sling out all the crud and deposits and clean oil was always sent back into the engine on each lap and that is why, those engine’s lasted for generations… Engine start up with zero oil pressure though is where you get the majority of your engine wear and is very hard to combat on any engine that does not have a pre-lube pump to get all that "motion lotion" flowing before crank starts to spin.

So post engine break in period and after your standard warm up, if you are running the engine long enough to remove the moisture (some period of or near WOT running before shut down) and are changing the oil as recommended, then for me the choice is clear and I will run synthetic. I though have never heard of it being possible for a synthetic oil to be "too slick" for rings too seal (which by the way, is not the rings primary job)... for if it was, then my fuel burn rates should drop by huge amounts (which they don't) from all that lost heat and friction from using such, true?

More information though on this interesting subject and the fairly recent release of “Marine Grade” synthetic 4 stroke oils can be found here http://www.amsoil.com/StoreFront/wcf.aspx for your viewing pleasure.

Enjoy!