Re: Mercury Oil or other Brand?
Actually, the egg beater test proves nothing other than the cheap gear lube has a lot of tackifier in it. (a rubber like compound that makes it adhere to metals.)
Alisyn (NOT Amzoil) makes a 0 weight gear lube that pours like water, but has as much high pressure film strength as 90 W dino gear lube. Boat racers run it in their lower units to gain a few HP. There doesn't seem to be any more wear than usual, and they run hot enough that the lube has to be changed every few hours.
Alisyn also makes a super 10W40 motor oil, and a 10W gear lube. They're the same formula in different cans. It meets the specs for both.
If you're running your engine in normal operating range, loaded so the WOT spec is met, and factory tuned (a little rich for insurance, giving up a few ponys), and TCW-3 oil if fine. If you push things like I do, it's worth while to use good lubricants. If you're racing, it's critical.
The Wal-mart TCW-3 is about the same as OEM standard grades. PennZoil half n half is about the same as the Premium grades. I run PennZoil full synth because I want the insurance and it smokes a lot less. It also costs less than standard mercury oil, which is a lot dirtier dino oil. I run Mercury High Performance lube in the lower unit, which is a 4 1/4 inch (XR4) dealing with about 175 ponys. I think if I owned a 200 HP motor like the one that started this thread, I'd use the same lubes I do now.
I like to buy used cars that are considered about over the hill, between 100 and 150 thousand miles on them, and then run them to between 300 and 400 thousand miles just by using good lubes (Wal-mart Super Tech full synthetic) and timely preventative maintainance. (plugs, timing belts, etc.) In salty MinnSnowta, the doors usually fall off before the engine fails.
Amzoil products are way overpriced and overbragged. Especially if you listen to their babble and try to run their oil at 100:1 in an engine designed for 50:1. Some of their claims aren't even relevant, like the claim that their oil wil runn at 400:1 without detonation. It's irrelevant because detonation isn't the failure mode for oiling, lack of oil film or film strength is.
In the above clip, the water seperation problem with the cheap oil would quickly do in a lower unit with a leaky seal. Any good marine gear lube has enough detergent and suspension agent in it to keep about 1/3 it's weight of water in a suspension that is relatively harmless to the gears. It gives you a chance to discover it (milky lube) and fix the problem. Amzoil gear lube is OK in that category.
hope it helps
John
