Hydrocruiser

Kaama's are cool

SeaRay Jim

I switched to the new Amsoil gear lube this season (can't believe I didn't gain 3 MPH like some have said they did. ) but I wonder if I should be running the Severe Gear simpley because I'm running close to 600HP through my B3 in my 3 ton tub. Although, when I drained the 2 season old Merc stuff, it looked good with no obvious sign of excessive wear. I'm pretty easy in the drive too though.

Ah, just one more thing to contemplate over the winter.

o2man98

Actually, the AGM Marine Gear Lube is a thicker than the Severe Gear 75w-90 when cold (40C). The main difference that I see is that the Severe Gear has a VI of 163 vs. 130 for the Marine Gear Lube making the SVG become the thicker of the 2 warmed up (100C).

Compare the specs:
AGM - https://www.amsoil.com/StoreFront/agm.aspx?zo=1132530
SVG - https://www.amsoil.com/StoreFront/svg.aspx?zo=1132530

Hydrocruiser

After going around in circles on marine gear lube I don't think you can do better than Mobil-1 75w-90. The only thing it dosen't have is the word "marine" on the package.

Rebel_Heart

How is the Mobil 75w-90 different than the Amsoil products? Are you able to purchase the Mobil product in local stores?

cloudmaster_321

Kinda a rookie question i'm sure, but in the Mobil 15W-50, what exactly does the numbers stand for?

cloudmaster_321

Would you prefer this over the merc high performance?

Hydrocruiser

The Amsoil Severe Gear and M-1 are very similiar. M-1 lubes are sold in most auto staores.

Hydrocruiser

A good synthetic drive lube and showers will extend the life of your drive maybe 30% I have found in working with boaters in my area who used to use the factory product.

Ove-heating and bad seals typically are what cause premature drive failures.

Hydrocruiser

Multigrade oils typically begin as base oils, such as 10W. Then viscosity-index modifiers (polymers) are added in an effort to stabilize the viscosity. This allows a 10W40 oil to flow like a 10W at cold temperatures and a 40W at higher temperatures.

The multigrade oils' viscosity modifiers are long-chain molecules that lessen the change of viscosity with temperature variance. In the past, the polymer additives (used to thicken the oil) were sometimes susceptible to viscosity loss. Permanent viscosity loss occurred when high shear forces (such as the relationship between the main bearings and the crankshaft) actually break the polymer molecules into less-effective smaller pieces. On a similar note, temporary viscosity loss also occurred when the polymer molecules aligned themselves in order to create a path of least resistance.

Fortunately, today's synthetic oil and additive packages have improved oil's shear-resistance. However, oils with the same rating from different manufacturers can exhibit different viscosity ratings in an operating engine, depending on the shear stability of their viscosity-modifying additives.

This means not all synthetic oils perform alike and the same goes for conventional oil too.