Yes, it can make the cone clutch slip and create delayed shifts into gear. Friend of mine bought a boat with 200hrs on Bravos. Prior owner ran Amsoil gear lube. Shortly after purchase it was having delayed shifts into gear. Swapped to Merc HP gear lube and issue went away. Also, not the first time I have heard of this happening with Amsoil gear lube.

This cone clutch thing comes up every once in a while here - if you Google, you will find more threads.

It just seems really weird that the tolerances are so tight that a slightly more slippery gear lube would cause issues with healthy drive. It seems more likely that the cone clutch is on the border line already, and going to a different gear lube exposes the problem.

(Then there is the separate issue of never using gear lubes with limited slip additives with cone clutches)

Griff,

Noted...

But this does come to mind. My recent experience tells me that factors other than simply slip of the cone clutch can contribute to delayed shifting.

Not questioning your observation. Just want to confirm the issues you relay were isolated to the switch to AmsOil.

Thanks. Brad.

Markus,

Speaking specifically to motor oil....

While I tend to agree with this sentiment, I've seen some pretty impressive torture test and bake test results that indicate AmsOil is a different beast. And, truthfully, it isn't that much more expensive than other mainstream brands, if any. My dad was diehard Valvoline Racing user. But I've found AmsOil to be pretty comparable, pricewise.

FWIW, I have typically been buying direct from AmsOil, but I have recently discovered I have a couple of local options that sell it for essentially the same price.

Thanks. Brad.

I think unless you go really cheap.....like a no name, back wood country store brand cause your lost and need it in a pinch, type oil, there are no really bad oils out there. Stay with a known name brand and you should be good to go. I was sold on Red Line oils years ago. I was at an NHRA race and watched their team drain the oil from the dragster they were running and put it into the tow vehicle and go home on that oil! I used Red Line on my old '99 Dually from day one and honestly i cant say there was any difference. Sold that dually with over 100K on it and it never burned a drop of oil. My 2010 Avalanche now has 225K on the clock.....been using Mobil1 for more than half its life...and the other half i have been using the Costco brand synthetic oil. I pulled the valve covers off about a month ago and it looks cleaner than any motor i have torn down in the past! Motor is all original and never been opened up. Only thing i did was turn the DOD off cause i hear too many stories about the motor getting wiped out from failed lifters. So something is working right
I feel it comes down to maintenance more than anything else...take care of the machine and the machine will take care of you.

I agree with that. I put Motul in my car the other day, but only because it was the cheapest oil I could find that met the manufacturer's specification.

My 300XS engines will run on Penzoil 100% Synthetic until my big stash runs out.

In the lower units, I use Volvo Penta spec synthetic from an autoparts store.

I've been running the "max machine works" recommended blend of amsoil severe gear with some lucas oil stabilizer in my Mr Gadgets built XRs. These were complete rebuilds, including the clutch, shafts, everything. They have held up well the past couple seasons with this combo of oil behind 800 whippled hp. I haven't had any clutch/shifting issues. I just had him build my spare drive with the endurance innovations lower gears, we'll see how those do eventually.

I think it's more the captain than the oil though.

I did so in perfectly shifting circa 1996 B1's and shifting got noticeably harder, notchy, and dry feeling. Switched back to Merc. and smooth as silk again.

That’s basically what I used.
1/2 quart of the Lucas and 2quarts of the standard duty amsoil marine lube

It gave the best life to the garbage XR upper gears

made the Amsoil switch 2 years ago now in both boats(xr's and b3's) and zero problems... no issues shifting or gear wear when i tore the xr's down this winter to replace the output shaft seals.