Amsoil Marine vs ATV vs Rotella T6

Aug 15, 2005
Southern Middle Tennesee
studying up on oils for a Seadoo GTI 130/155 and have found these 3 options. my question is why would anyone use the Marine with a lower TBN and higher 4 ball wear test than the ATV specific Amsoil. plus the ATV is 0w40 instead of 10W40 and then you have Rotella T6 5w40 that is known to be a very good oil that will work for my situation and is a lot cheaper than Amsoil. and i am an Amsoil dealer. then to muddy the waters even more i read any 0-10w40 i.e. mobil1 or Pennzoil will work since i don't have the supercharger. just want to get anyone opinion on here as to what they run and why.
as you know, I'm new to SeaDoo, but I have been maintaining boats, snowmobiles, atv's for 30 years. BRP's own oil is a 5w-40 semi-synth. for winter, they recommend full synth. (SkiDoo) I find it odd that they dont spec a full synth year round. you also know that Amsoil has specifically created a marketed oils that are very specific to the exact use. this is largely a marketing effort. if you can create a demand for your product via fear, uncertainty, and doubt, the customer may be more likely to purchase your specific marine oil instead of a genreal purpose oil. I suspect there is very little difference between Amsoil's marine and utv oils. theoretically, your use is closer to marine: non dusty environment and liquid cooled. I doubt that TBN is a large concern - unless you run tons of hours on your unit. I know that many rental outfits have 1000+ hours on their SeaDoo engines. I am curious what oils they used. I know from tons of marine experience, that many high-use boats use Rotella and/or Delo (basically HDEO oils) with great long-term results. Personally, I will use Rotella or Amsoil Marine and not worry a bit.
I have been using NAPA 15-40 Universal Fleet oil for 8 years in my F115 Yamaha. Never had a problem. Just two weels ago I walked away while flushing the motor and forgot to turn on the water. Came back to rubber smoke and an alarm. Melted the pump bad enough to ruin the upper gearcase seal. Repaired all that and it ran great. I changed the oil and no worries. I sent the oil to Blackstone with an explaination and it came back still useable. No Syn for me in my outboard cause I change it at 50 hrs anyway. That oil is made for NAPA by Valvoline.
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The 130/155 is not supercharged so you can run pretty much what you want in it. I would go with a think 30W (GC) or a 40 weight as these engines work hard and run hot. I run Castrol 0W40 in my 155 RXP, and T6 5W40 in my GTR215 due to the wet clutch requirement
I would simply use whatever meets the spec and change it at a reasonable interval. Oil related engine failure isn't what's going to kill a modern, 4-stroke, naturally aspirated PWC such as yours. If it's a brand new Sea Doo GTI, I would instead obsess over appearance care-- helped my parents buy a 2018 GTI Limited 155 to update their 2013 version of the exact same after it passed 200 hours and was going to need a little work (cracked gauge cover, worn seat upholstery). Boy, was that a mistake! Compared with the older machine, on the 2018, after just 30 hours: the factory cover is less durable, the quality of the upholstery got worse (thinner), the quality and durability of the gelcoat got worse, the stupid CM-Tec deck material is already showing spider cracks where no impact could have taken place, the floor mats were coming unglued from the deck, the 2018 machine is louder and heavier than the 2013 version, and the programming for the digital throttle in 'normal mode' is absurdly sluggish on the new machine.
I have a 2006 Honda R12X Turbo. I run Amsoil High Zinc 10w40 in it. It has 654 hours. Runs like a dream. The boost is a bit higher than stock as well. I run Amsoil Marine 10w40 in my 2014 Supercharged RXP-260. That one also runs extremely well. 252 hours on that one. I went with the Marine spec oil in this one mainly because Amsoil tested it to work great with the Seadoo wet clutches. If I had a new GTI I'd probably go for the High Zinc Amsoil.
Originally Posted by alarmguy
Originally Posted by CT8
Less viscosity improver
Yeah … plenty 15w40's are better for many applications and T6 never even had a decent Noack
Originally Posted by Arctic388
for now i have decided to run Rotella T6 5w40 in both my Seadoo GTI's with a K&N 556 oil filter.
Good Choice on the oil. BRP has dropped the price of OEM filters, no reason not to use then.
Here is a marine oil I spotted at the parts house … impressive properties including Noack