Quicksilver 80w-90 for lower unit F115?

[rodbolt17]

the Volvo GL5 is now 17.99 a qt.

you outta price the seastar steering oil.

[DennisG01]

best I recall the GL4 merc HP gear lube was a semi synthetic.

the GL5 Volvo and the Yamaha HD are full synthetics.

I can tell ya a story bout a man named Bill.

he was a close friend and crabber and old .
I took care of him and Naomi,his wife, best I could for 20 yrs or so, both passed in the passed two years .

Bill did not believe in much maint on his F50 that I gave him so I used the Volvo GL5 in the assumption that it would last longer .

about 2 years into it Bill called me about a rattle in the lower.

at disassembly I found the bushing in the fwd gear that rides on the propshaft peeled out.
not wiped or worn simply peeled out.

that's when I found that full synthetic oils and bushings don't get along.
its also why Yamaha says NO GL5 oils unless the lower is specifically rated for it.
I asked at school one year and the instructor got an engineer to answer.
the additives in the GL5 oil can be corrosive to certain bushing materials and the molecular structure of the oil wont properly lubricate bushing.

the fwd gear bushing on the F50 is not on the parts list and you buy a gear.

so if your POSITIVE your unit has NO bushings then run the synthetic GL5 if you wish.
if your not positive I would stick with a GL4.

As always, thank you for the information, Rodbolt. Believe me, if there is ANY question as to whether or not the Merc HP will work in my OX66 250, there is no way I will use it. Just because I have such easy access to the Merc stuff, does not mean I will chance damaging the lower unit.

I have (and can get) the Merc stuff in bulk and have it already loaded up in my gearcase filler. Hence the reason for wanting to use it. Partly because of the easy access bulk thing, but also because (as you know, I'm sure) it's SO MUCH nicer to fill the gearcases with the gearcase filler as opposed to pumping it in 1/2 oz at a time!

[DennisG01]

Long time in coming, but I finally talked to Merc. Was told that the "GL" ratings are more of an automotive thing, but the Hi-Perf gear lube is GL-4 rated and definitely not GL-5. I also talked with a local Yamaha dealer who said the Merc stuff is perfectly fine for the Yamaha gearcase - they even went on to say that the Merc stuff is some of the best gear lube on the market and they use it, too.

[rodbolt17]

ughhh, find real techs.

[DennisG01]

I think what he was trying to tell me (although maybe a little too enthusiastically) was just that it's good stuff and I'm fine to use it.

Out of curiosity, is there a drive lube that you tend to prefer over everything else? I'm not opposed to using something else - it's just that I have so much of this Merc stuff in my garage that as long as it's not going to cause any problems, I'd likely use it.

[bajakeith]

Dennis

I maintain a pair of oxxy's 250's on a 28 Boston "Conquest" Coast Guard AUX patrol vessel....been using the merc oil on them since day one and no problems at all....and GL 4/5 has nothing to do with cars that I know of

[DennisG01]

Keith, do you use the Hi-Performance stuff (bluish-green) or their premium stuff (the premium is a normal colored oil, and actually not as good of a product as the Hi-Perf)?

I believe the GL4/5 thing and autos is in regards to differential gears. Not that that's the only thing, but I think that's the most commonly seen place that these ratings are used?

[fairdeal]

"API Category GL-4 designates the type of service characteristic of spiral-bevel and hypoid gears in automotive axles operated under moderate speeds and loads. These oils may be used in selected manual transmission and transaxle applications.
API Category GL-5 designates the type of service characteristic of gears, particularly hypoids in automotive axles under high-speed and/or low-speed, high-torque conditions. " - Lubrizol Corp

I've read that "A normal GL-4 gear oil of any given viscosity has about ½ of the level of sulfur/phosphorous additive that would be in the GL-5 product"

Apparently its the sulfur that can eat brass...

[DennisG01]

Fairdeal, after learning some new information through this thread, some googling, and finally your post, it's all making sense, now. Apparently the sulphur/phosphorous/brass thing deals with some type of protective layer that the sulphur/phosphorous creates on the surface of metals. With steel gears, when that protective layer is worn off, everything is still OK. But in the case of brass (or other soft metals), the bond between the protective layer and the brass is stronger than the brass. So when the protective layer is scrubbed/peeled off, it takes some of the brass with it. GL5 has much more sulfur/phosphorous than GL4 - fine and dandy for steel gears, but not so much for the softer metals.

Very interesting stuff!

[bajakeith]

gears and lube

As I stated before..its not about cars !! its about gear's,,axle's,tranny's,,PTO's and a host of gear driven unit's...

[Nautical]

What happens when you use a GL5 rated oil is that the additional antiwear components like sulphur absorbs moisture and water. When combined it forms sulphuric acid. The acids will wear away soft brass and other metals. Great for a non water environment , not to be used where moisture is induced such as a marine environment.

[DennisG01]

As I stated before..its not about cars !! its about gear's,,axle's,tranny's,,PTO's and a host of gear driven unit's...

I was paraphrasing what the Merc tech was telling me, but he/I used the term "car" loosely. Meaning, he was talking about the automotive world (in general) as opposed to the marine world. He wasn't going into a lot of detail, but from how he stated things, he was basically saying the same thing as you. He was just using the automotive reference as an example - auto, truck, tractor, whatever - he was really just differentiating from the marine world and lower units which DO NOT use steel gears (at least the ones that we were talking about in our conversation).

[rodbolt17]

the GL is an API rating. API is an engineering institute.
its an engineering term indicating what the oil should be used for.
the merc HP is a semi synthetic that I have seen used in various gearcases for years with no issues.

do NOT use full synthetic GL5 in any gearcase that does NOT specify the use of GL%.
I thrashed a friends F50 case using GL5 Volvo oil.
it peeled the bushing out of the fwd gear.

Volvo uses it in certain drives cause some of the Volvo drives have NO bushings.
same as some yamaha's use GL5 HD yamalube as some large yamaha's use no bushings.

just after the F350 came out I was at school in Kennasaw, I asked why do we have to stock two gear oil types.

a few days later the engineering dept told us that the GL5 would not properly lubricate a bushing.

and that's when it dawned on me why that F50 bushing looked like it simply peeled out and slid fwd,

[bajakeith]

on a side note

Sir Rodbolt is correct and the Volvos he is talking about are the DP with the sliding clutch..Volvo states " if your in a piss poor third world place.. you can use syn Mobil One".....LOL

[seahorse5]

Not all GL-5 oils will damage brass or bronze items, but you would not know which ones were OK unless you were privy to the ASTM corrosion test results for the product.

The latest and greatest hi-tech high-priced lube is not always the best for your motor.