Using 75W90 Synthetic Gear Lube in Bravo 3 Outdrive-gctid372404

[Guest]

I am considering using full synthetic 75W90 gear lube(Mobil 1 or Amsoil) in my outdrive in lieu of the manuf recommended mercury lube. I have had great results with synthetic oil and gear lube in my automobiles so figure it may be good for the boat as well. What are the pros/cons to using the synthetic versus the petroleum lubes?

[dktool]

I have been using the Amsoil synthetic marine gear lube for years in both merc alpha drives and omc cobras.

Works for me !

And it's the color of beer, it has to be good.

[Guest]

I read in another website that the merc/quicksilver lubes have a friction modifier that is required to properly operate the cone-type clutch in the Bravo 3s. Apparently the Amsoil and Mobil 1s do not have the modifier. I don't fully understand the operation of the clutch(looked for a schematic dwg but could not find). Any feedback as to how this clutch functions and the affect of a non-friction modified lube on the clutch is appreciated.

[bhawes]

For the cost of the recommended lubricant (which I believe is less thsn the synthetic that you mention), why flirt with Murphy? Sierra also sells an approved ???? lubricant for Merc's. for a little less $.

[Eyeman]

ChillinDaMost wrote:
I read in another website that the merc/quicksilver lubes have a friction modifier that is required to properly operate the cone-type clutch in the Bravo 3s. Apparently the Amsoil and Mobil 1s do not have the modifier. I don't fully understand the operation of the clutch(looked for a schematic dwg but could not find). Any feedback as to how this clutch functions and the affect of a non-friction modified lube on the clutch is appreciated.

Listen to this person folks. I can not speak to marine application B3 clutch systems, but do know that when I switched to the Mobil 1 synthetic in a factory install Dodge Ram 1500 Dana rear differential it took out the limited slip clutches. I was supposed to have added a "friction modifier.ÔÇØ It made me very conscious of using the exact specified gear oils in all of my equipment. Though I will say that I have a 1996 175 Mariner that has always used the Mobil-1 and it's never failed me. No leaks, perfect color each fall when it's drained and changed.

[2850Bounty]

ChillinDaMost wrote:
I read in another website that the merc/quicksilver lubes have a friction modifier that is required to properly operate the cone-type clutch in the Bravo 3s. Apparently the Amsoil and Mobil 1s do not have the modifier. I don't fully understand the operation of the clutch(looked for a schematic dwg but could not find). Any feedback as to how this clutch functions and the affect of a non-friction modified lube on the clutch is appreciated.

I don't believe that there's any way to compare bearing/gear lubrication to that of cone clutch lubrication. It's a fine line and a double edged sword, so to speak.

We want bearing and gear lubrication at it's best....., but the sliding sleeve and gear cups must over-come lubrication, and lock up.

If the two do not fully lock up, you could have problems.

Some of the older Volvo Penta brass sliding sleeves and gear cups do not lock up when synthetic gear oil is used.

Not sure how this relates to Merc's B drives, but I think I'd stay with what they recommend.

.

[Guest]

As said above! If your drive units have any form of brass syncs of any other part in there and it's brass and you use a GL-5 based gear lube, I can tell you it will eat those brass parts fast due to the high sulfer content in a Auto approved gear GL-5 rated lube. From my understanding the marine gear lube has additives in it to help with water intrusions. ie like corrosion additives and I'm sure many other thing that help play with moisture.

[captharv]

Being a retired engineer, I believe stongly in "if it ain't broke, don't try to fix it"

The engineers will test many lubes before deciding on which one has the best performance and causes the least wear (and problems).

Nowdays, you can get extended warranties thru the manufacturer for 7 years. The manufacturers are not interested in providing major parts under warranty, so they choose their lubes wisely. If it is designed to make a product last longer and/or get higher performance than another lube, do not try to second guess them, especially at over 4 grand for a replacement drive, unles you are educated in this and have testing facilities.

I buy the mercury lube recommended for the drive. I have owned 4 mercruisers, and have never had to have a drive rebuilt. I over maintain, if the book says change at 100 hrs. I doso at 60-75. same with the engine oils. My recreation time is valuable to me and don't want to have problems.