Mobil One Synthetic oil

W

Will-C

New member
Hello,
I wondered how many people run synthetic oil in their four stroke outboard engines. Some say the synthetic oils attract moisture. I run it the family fleet of cars and truck. I change it once a year or at 15 thousand miles. I wondered if it made sense to use it in outboards. Always had two stroke outboards in the past. How many hours do you put on before you think about changing your oil?
D.D.
 
I don't put high hours on my stuff so I can't address that part. I do annual oil changes with Amsoil on the fleet and Honda outboards. There has been no evidence of water contamination in the outboards or other stuff.
There is an honest Amsoil rep that posts on a Harley forum I frequent, I'll ask him about the synthetic oils attracting moisture.
 
Dave-

I don't run synthetic oil in my outboards, but do use Mobil 1 in my Sea Ray V-6's. Change it once every year, which is only about 50 hrs. The boat has run it for 20 years and runs like new.

However, my mechanic (who does the difficult stuff I can't), says Mobil 1 or any synthetic is not necessary in an ordinary marine engine.

Translation: Daytona Eliminator with twin blown 500+ cu. in. engines= yes, Ordinary OMC V-8 = no.

Outboards= ? They do work harder than the typical automobile engine application, so maybe a high temperature tolerant oil may be an advantage.


You can find all kinds of discussion on this topic on The Hull Truth, lots of it directed at Amsoil, another synthetic oil.

Joe. :teeth :thup
 
There is a marine spec for corrosion inhibitors in 4 stroke oil . Suzuki feels it is very important .They have some info and pics of corroded metal in an outboard from using automotive spec oils. Synthetic does not meet that spec as far as I know . After break in , 100 hour changes are called for by the motor mfgs. Its a good question , but we stick with recommending the motor manufacturers oil . That way if there were and oil related problem , not that we have had any ,they would have no "out"
Marc
 
The manufactures don't have a way out. There's a law on the books (I can't quote it right now) that states if a manufacturer requires the use of their oil only, then they have to furnish it for free. As long as you use an oil, synethic or not, that has the same specs or better you are fine. I personelly run synthetic in all my motors and have for the last 25 years with no problems. There was a test run a while back in one of the boating mags that tested corrosion protection using four or five different outboard oils. I don't remember all the brands tested but do remember that Yamaha brand oil came in last.
I would suggest before changing over to a synthetic oil on a new motor that it be broken in with the manufactures oil. I usually run mine one season or 100 hours ( seasons are short up here) then switch over.
 
Nunya, you're thinking about the Magnuson Moss Warranty Act.
Whether conventional or synthetic oil is used it's probably a good idea to make sure it's designed for marine service.
 
Mercury Marine, I have a Merc 90 4stroke, has there own synthetic oil which they recomend using. I only have 110 hrs on my engine so it is to early to tell. So far all is well.

Chuck
Bootleg Hooch
 
I've used Mobil 1 since the first 20 hours, and now have about 975 trouble free hours on the Honda 90. Mobil 1 meets or exceeds all Honda oil reqirements. Would never use anything else. The recommended oil change cycle is 100 hours. I'll usually change oil at or about 100 hours, and filters every other time. End of season, it gets a new filter and fresh oil, no matter what.
 
I've been running some sort of synthetic in all my engines since about 1980 when I was a dealer for Amsoil. I let the dealership drop, but I still use synthetic oils.

Don't use it to break in the motor. But once broken in it will work great.

Back when I was selling the stuff. The only other manufacturer of synthetic oil was Mobil 1. Both of them far surpassed anything else on the market at that time in all categories except breaking in a motor. These days, I typically use Castrol Syntec in my car and truck simply due to it being available at the service counter.

My new motor for the C-Dory will be broken in with non detergent 30w dino oil if I can find it. Then it will have one of the synthetic oils put in for the rest of the time I own the boat.
 
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