F80-F100 'B' series gearbox issues

[boscoe99]

I looked at a number of gear cases for other models and in a number of cases could not find a specific part referred to as a bushing. However, there may be other "yellow metal" parts used in those gear cases. In which case GL5 oil would not be approved.

There are many, many hundreds of different Yamaha gear cases.Let's say 500 for the sake of discussion. Of those 500, Yamaha knows for sure that the SHO gear cases, the Offshore gear cases, and the V8 gear cases do not contain yellow metals. So, GL5 is the approved oil for these models.

Of the remaining 497 different gear cases, going back to at least 1984 here in the USA, and further back still in other parts of the world, some may have yellow metals and some might not. So, rather than spending a lot of needless time trying to determine which, if any, might use or not use yellow metals, Yamaha simply says use GL4 rated oil in all of them. Erring on the safe side.

Once your lowers are torn apart it would be nice if you could take a good quality digital picture of the break. Cleaned of gear oil of course. Would be nice to see if it is a fatigue fracture or an over stress failure.

[rodbolt17]

the bushings in the fwd gear,reverse gear and some drive shaft housings are NOT replacable and are NOT sold seperatly by Yamaha.
most older v6,v4,inline and tiny mite motors have one or more bushings.
did not see ANY corrosion on that f50 bushing it just peeled it out of the fwd gear bore and stuffed it forward into the shift shaft area.

first and only bushing failure I ever saw and it occurred about 8 months after I switched it to GL-5 syn.

that was about 4 yrs ago.
since then that unit gets GL-4 mineral oil.
no issues since but I do have old man bill a spare case.

[almetelo]

Hi!

Just after reading this thread I realized I'm using GL-5 geal oil on my F100, F4 and 30 x3 2 strk

Since we are almost in the end of main season for boating for me is time for maintainence and replace this gear oil soon as possible by the GL-4

I've been reading a little about gear oils and found this very interesting

http://www.widman.biz/uploads/Transaxle_oil.pdf

(if you don't have patience to read all just read the summary however confirms what alread have been told here)

I was trying to find SAE 90 GL-4 on auto market (have a friend with car parts shop and can get much better prices here intead of Yamalube products)

This may also be usefull

http://www.kuttenkeuler.de/kkweb/Dow...jectId=1000462

[boscoe99]

Good read Mr. Almetelo.

Once again, after all else fails, follow the directions.

[madharchod]

since yamaha has been involved in china made parts the oil has become very important
use hypoid gear oil you will have no problem these engines are not like cars the gear boxes of outboard work excessively hard under extreme cases