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BF200 black gearcase oil question

Blacktimes

Regular Contributor
Changed the oil in both gearcases today on my BF200´s. Starboard oil was brand new and clear, I was really surprised, port oil was black, black, black. No abnormal findings on either chip detector. Have been searching the internet and the consensus is not to worry about black gearcase oil. Last change was also done by me, same oil in both units, same hours, etc. Both engines work fine, no abnormal noises, vibrations, etc. No traces of seawater mix (milky). Any idea why one oil is brand new and the other black? Should I be concerned? Thanks!
 
Need to explain the ---" extra gear "--- in a counter rotating lower unit.
The linked thread has an explanation. Short version is the outboards motors all rotate the input shaft to the lower unit in the same direction so an extra gear/cog is added to get a reverse rotation. The pinion gear is the same in both lower units in the Yamaha regardless of rotation. The extra metal in the lower unit results in more heat while running plus you have room for less gear oil. I’d use synthetic in a reverse rotation outboard, it remains good/ no breakdown in a wider range of temperature.
 
The pinion rotates.------One gear rotates one way and the other gear rotates the other way.-----Where does the extra gear need to fit ????----What model Yamaha has the extra gear ?
 
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No extra gear. The reverse gear is forward on the propshaft instead of at the back of it. The counter rotating gear set is, simply put, backwards to the right hand gear set.IE: reverse gear forward and in mesh with the pinion and the forward gear engaged by the dog clutch

The gears are cut a bit differently and, according to post #12 by Andy there is an extra bearing and additional shims. I don't know, I've never been inside a CR gearcase and his picture links wouldn't open for me.

I didn't know that the CR gear sets made so much extra heat (and thus wear) and need pretty much twice as much preventive maintenance.
 
Yes, and that would make sense if there are a few extra pieces in there or if the physical size or shape of a part was displacing some space that would otherwise be reserved for oil.

But....

....and I'm just shooting from the hip here since I don't actually know...

I think the small amount of gear lube "discrepency" likely contributes less to the issue than running the transmission in what is, essentially, high speed reverse to go forward.

I'm guessing that reconfiguring the gear train in order to accomplish that task is the real culprit in creating more friction and heat.

The engineers probably deem the losses acceptable and it's dang sure cheaper than manufacturing a right AND a left hand rotating engine.

All a big guess on my part and I will now await the torching I have coming from thems that knows.
 
Oil quantities are the same. The diff with counter is the usual reverse gear had a tapered bearing and the standard forward has a ball bearing.Black oil is an indication the mesh is not correct causing more heat generation. Not really an issue but longevity is reduced long term
 
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