Synthetic lubricant is great and better then mineral oil in many applications. Of course there are different synthetic base stocks and additive packages. Same with mineral oil.

The issue with synthetic, is during extreme pressures on a bearing or contact surface, (read bearing shell/journal, gear contacts, ring to bore contacts) the synthetic curve film strength tapers off. Allowing metal to metal contact.

Mineral oil, the film strength is linear, till it's concrete.

Mild engines...use good full synthetic. Anything on the higher end of cyl pressures and crank rpm, high load gear mesh, like an outdrive, use a good semi-synthetic.

Then you get the best of both worlds.

Cone clutches, just like flat tappet lifters need to have some friction IOT operate. Clutch type limited slip differentials spec friction modifiers so they can do they're job without slipping more than intended.

My last boat I used the Merc green-ish-blue whatever crap in the B1's. Changed every season on both and it always came out very shimmery w/ metal and the oil in the reservoir would coagulate in the bottom of it. When I first got the boat the reservoirs were really fouled up because of it. Switched to Amsoil marine gear lube and both of those issues went away. I'll never use it again if I have Bravos.

AMSOIL 75W-90 100% Synthetic Marine Gear Lube | AGM - AMSOIL

Quicksilver extreme performance (amber stuff) is what someone on the engineering team at mercury recommended to me. I've used it in all bravo applications and have never had an issue

Anyone using Neo gear oil?

Padraig

I bought this and it doesn't say synthetic anywhere. It does say to shake before use!! Never saw that before and of course I didn't do it. Why am I suppose to shake a qt of oil before use?
https://cimg0.ibsrv.net/gimg/www.off...faddf5794b.jpg
https://cimg3.ibsrv.net/gimg/www.off...8c5c8508c1.jpg

because all the additives have settled on the bottom

that is not the 85w-90 extreme lube....

Where on earth did you learn that?

These are all quite similar molecules, but the ones in synthetics (as in PAO and ester-based lubricants) are closer to perfection. It is not like they behave fundamentally different.

I made the switch to neo from the standard merc bravo 1 oil this year. First trip out I noticed smoother shifting and the slight hum noise before was gone or at least quieter from the captain’s chair. Only a couple run hours into this neo oil but so far so good

What weight Neo are you using?

Padraig