What is the best 10W30 oil.

Would the newer viscosity Mobil 1 75-140 gear oil be a better choice for high horsepower bravo drive protection than the original viscosity 75-90? Anybody used this oil or have any thoughts?

Yes, the only draw back may be a slight horsepower loss due to the heavier viscosity. I have used nothing but a full synthetic 75w-140 GL-5 in my lower units, both Alphas and Bravos for the past 10 years with no problems. I personally perfer a heavier viscosity oil because viscosity is your first line of defense against wear. Additives like zinc and EP additives are reserve boundry lubricants, they only work when the oil film has been compromised.
You will be doing just fine using a 75w-140 gear lube in your lower unit.

Happy Holidays, Ken

Any idea how the Hp loss from Redline Shock Proof (Heavy) Gear Lube would compare with the 75w-140?

I doubt you will notice the difference in top speed. Ken

Ken, Thanks for the feedback on using 75-140. Is the 75-140 a higher viscosity than the Merc Hp green stuff? I'm using the Merc now and am eating lower gears. I'm looking to change to something heavier in viscosity.

I am sorry, I have never used the merc stuff and they don't put the viscosity on the label. Lf you are eating gears the only thing a heavier lube will do is prolong the eating of the gears. You have a lower unit problem. Ken

Still interested in suggestions. For general use in Yamaha Wave Runners.

Rage, you can use any high quality motorcycle oil in your Waverunner. All the benifits that your boat engine receeives from quality oil , your watercraft engine will receive. If this was mine I would use Spectro 4 10w40 motorcycle engine oil. It is a straight petroleum with the uptreat in anti-wear chemistry. change it once a year.

Ken

Thanks Ken. So the key is using a "motorcycle oil" for best quality oil. Yamaha markets a 10W30 "Yamalude" oil for their PWC units. It looks rather clearer than lets say Penzoil 10W30. Anything known about this Yamalude oil? Just looking for the best oil to use to keep them a long time. Oil is cheap wave runners are not.