F80-F100 'B' series gearbox issues

[AusGeorge]

Hi Guys an Gals

I'm interested to hear if anyone is having issues with the new 'B' series gearboxes?
I have a customer that is running 3x F100's, had them for 8 months now and every motor is now on it's third gearbox. All have shattered the forward gear teeth. They are used on hire drive boats, so they do get used hard as you would expect. But this is getting beyond a joke, he had the 'A' series boxes for three years and did one box, new engines and 6 in 8months. Alarm bells are ringing for me.

Interested to hear if this is happening on a wide scale

Cheers

[TownsendsFJR1300]

I've read Yamaha does NOT recommend Synthetic oil in the gear box.

Don't know if that may apply in your situation...



Is Yamaha stating anything re the failures (as your sending the broke LU's back)?

Just curious, are you "feeling" and excess play in the LU drive shaft or prop shaft in the new units?

Is the shifter cut off switch (by the under cowl shifter assembly) working(just a shot)?

[boscoe99]

Provide an engine serial number or two.

There have been some F75 - F90 gear changes here in the US.

[boscoe99]

Some other thoughts come to mind.

Are operators of the motor given advice to not shift it into and out of gear unless it is at idle RPM? In my wife's case she starts her car in the morning and it revs up because that is what Ford's do. Before it has had a chance to idle down she drops it into gear and steps on the gas pedal. I just wince and keep my mouth shut when I am with her.

Is the motor propped so as to lessen the loads on the gear set when it is shifted into gear? Having a propeller pitched such that the motor can run at or near its redline of 6000 RPM when at wide open throttle, with the boat loaded, will mean less pitch, or blade angle. Less blade angle means less shock loading of the gears when the motor is shifted into gear.

Most motors are over propped meaning too much pitch or propeller blade angle.

Yamaha offers a new series of propellers known as "Talon" that will fit your motor. The hub of this propeller has a shift dampening mechanism that flexes to reduce the shock load on the gear set. You might want to look into this type of propeller. A lot cheaper than replacing gear sets.

[AusGeorge]

Hi Guys
Thanks for the input. I'll try and answer a few of your questions.

*The LU's are for a customers 'hire drive' boats, so I don't see any of the new units before they go onto the motors, so I cant answer any of the questions relating to that.
*The LU's are being supplied by the local Yamaha dealer, they seem to think that there is nothing abnormal about the amount of LU's they are going through.
*My customer has always been using yamaha lower leg oil until very recently, they have just changed over to full synthetic to try and get improved life out of the LU's. I've been in the auto and marine mechanical industry for about 20yrs, and I can't see the reasoning behind the Yamaha box's not being suitable for synthetic. Happy to be proven wrong but it seems a bit of a weird statement from Yamaha
*Operators are given a run down on the boats and how to use them prior to going out, this is one of the mandatory requirements for hire&drive vessles over here, not to say that the average joe cares much.
*The local Yamaha dealer dosen't take the LU's back, they have made it pretty clear to my customer that they really don't care.
*All props are OEM Yammy, they get a pretty good price on the alloy units so they just replace them as needed.
*I'll have to wait until the motors come on for a service to get serial no's, I am aware of the changes in gears for the boxs, from memory they have gone from 30T to a 25T, this is from what I understand is the change over to the 'B' suffix box. This is where the trouble has started.

My thoughts are that they have changed the gearing too low, increasing the torque through the gears, they have also Ni coated the gears and tempered them to make them stronger. I think that the gears are too hard and with the extra torque load through them it is causing the gear teeth to break.
Just my thoughts, but it all seem too much of a coincidence that they make these engineering changes and all of a sudden gear start breaking on a regular basis
I'm very tempted to get a gear set, send them away get the hardness tested, then get them re-tempered so they are not so hard. Just gotta find a place that can do it at a reasonable price.

Any more thoughts would be appreciated.

Cheers

[TownsendsFJR1300]

Hi Guys

*My customer has always been using yamaha lower leg oil until very recently, they have just changed over to full synthetic to try and get improved life out of the LU's. I've been in the auto and marine mechanical industry for about 20yrs, and I can't see the reasoning behind the Yamaha box's not being suitable for synthetic.

Any more thoughts would be appreciated.

Cheers

I can tell you, Rodbolt (Full time mechanic, many decades of experiance) posted recently, re full synthetic, LU oil as the issue came up.

At a Yamaha school he went to, it was specified NO SYNTHETIC LU OIL. Two failures as I re-call, one he personally had to fix which had synthetic oil, BUT it had to do with bearing failures, NOT GEAR failures.

Perhaps once the bearing fails, if run hard enough, it takes out a gear.. He was very adament about it, the issues and it was proven to him NOT to use it (good enough for me)


That alone, I'd be running regular Yamaha LU oil.

Heck, your changing the LU oil more than once a year with all the blown up lower units anyway!

*Once those enignes are out of warranty, hope you have a thick wallet!

For all those lower units to keep blowing up, and believe its normal, its beyond me...

The F150 had balancer issues which Yamaha addressed several times (under warranty) with several updated and fixed balancer units...

[rodbolt17]

some years back on an F50 that a friend has and changes the gear oil about once a year whether it needs it or not on a commercial boat.

I started using the Volvo GL-5 syn oil.

one day he called me about noise in the box.

I tore it down and the bushing in the fwd gear that rides on the propshaft had peeled out.
never saw that before so I rebuilt the box.
some months later at Kennesaw doing a school an engineer was there for a Q and A session.

I asked why did we have to stock two gearlubes.
the HD synthetic and the regular Yamaha lube.

the answer.
the molecular structure of the syn oil was to big to properly lubricate a BUSHING.
you can only use synthetic gear lube in cases that use NO bushings ONLY needles,balls and rollers.

4 years or so ago I switched that F50 back to mineral based and its still chugging.
BTW the old man that owns it crabbed yesterday on his 80th birthday.

this F50 is on a 21' privateer and is a tad underpowered we cut down a 12 1/4x9 to an 11 1/4 x 8 to keep the RPM near the 6000 mark.

[boscoe99]

Hi Guys
Thanks for the input. I'll try and answer a few of your questions.

*The LU's are for a customers 'hire drive' boats, so I don't see any of the new units before they go onto the motors, so I cant answer any of the questions relating to that.
*The LU's are being supplied by the local Yamaha dealer, they seem to think that there is nothing abnormal about the amount of LU's they are going through.
*My customer has always been using yamaha lower leg oil until very recently, they have just changed over to full synthetic to try and get improved life out of the LU's. I've been in the auto and marine mechanical industry for about 20yrs, and I can't see the reasoning behind the Yamaha box's not being suitable for synthetic. The issue as I understand it is not synthetic versus non-synthetic but rather it is the API GL4 versus GL5 rating. The specification for the F90 here in the USA is GL4. If synthetic oil with a G4 rating is used there should not be a problem. Happy to be proven wrong but it seems a bit of a weird statement from Yamaha
*Operators are given a run down on the boats and how to use them prior to going out, this is one of the mandatory requirements for hire&drive vessles over here, not to say that the average joe cares much.
*The local Yamaha dealer dosen't take the LU's back, they have made it pretty clear to my customer that they really don't care.
*All props are OEM Yammy, they get a pretty good price on the alloy units so they just replace them as needed.
*I'll have to wait until the motors come on for a service to get serial no's, I am aware of the changes in gears for the boxs, from memory they have gone from 30T to a 25T, this is from what I understand is the change over to the 'B' suffix box. This is where the trouble has started. Here in the USA with the F90 the gears were changed beginning with serial number 61P 1051636. The gear teeth number were reduced in order to make the gear teeth larger. Pinion gear went from 13 teeth to 11 teeth and the ring gears went from 30 teeth to 25 teeth. So, the gear ratio has changed but it is higher, not lower. Gear ratio in the latest model is 2.27/1 versus 2.31/1 in the earlier gear case.

My thoughts are that they have changed the gearing too low see comments above, increasing the torque through the gears, they have also Ni coated the gears and tempered them to make them stronger. I think that the gears are too hard and with the extra torque load through them it is causing the gear teeth to break.
Just my thoughts, but it all seem too much of a coincidence that they make these engineering changes and all of a sudden gear start breaking on a regular basis
I'm very tempted to get a gear set, send them away get the hardness tested, then get them re-tempered so they are not so hard. Just gotta find a place that can do it at a reasonable price.

Any more thoughts would be appreciated.

Cheers

See comments above.

You can go to the parts catalogs at Yamaha Outboards and see the part numbers used in the earlier and later F90 gear cases. It even shows the number of teeth per gear and the engine number serial change for the teeth change.

The USA F90 owner's manual specifies 90 weight hypoid gear oil for the lower unit. The service manual specifies 90 weight hypoid gear oil to specification GL4. No prohibition against the use of synthetic gear oil is stated.

[boscoe99]

What is your relationship to Yamaha Australia? I presume that is where you are?

What is the part number for the lower units they are supplying to you?

You mention the hire boat operator as being your customer. Are you a Yamaha Australian dealer?

Unfortunately, when it comes to commercial applications Yamaha Japan is not too friendly when it comes to goodwill support. Maybe they feel their own product is not robust enough to withstand frequent usage.

[AusGeorge]

Hi Guys
Thanks for all the feedback, all appreciated.
I'm not a Yamaha dealer, we are a marine workshop that services,repairs all makes of outboards. An yes we are in Australia.
Rodbolt, I understand and appreciate your advice on the synthetic debate and agree totaly with what your saying on the grades.
I would however have to agree with Boscoe on the grading, if they are rated to GL-4 and you can get a GL-4 syn then it should be fine. After all my customer has only just changed over to the synthetic. The 5x LU's I have in the workshop were all running on Yamelube, so I think for the time being that's not part of the argument.
Boscoe, very right on the gear teeth count. Not sure how I read that wrong from the beginning. I can understand trying to make the teeth bigger and stronger, but it dosn't seem to have worked for them. And your correct, Yamaha Aust. has not time for commercial operators whatsoever. It's why the market is very quickly swinging over to Suzuki's over here.
Townsend, unfortunatly over here as soon as the commercial customer walks out the door there is pretty much no warranty, they have talked their way out of every warranty claim to date, all the replacement gearbox's have come out of my customers pocket. The motors are just nudging 9 months old and he is looking at ditching the lot and changing to Suzuki. 6x boxes could have bought him 2 new zuks by now.

I'll stick up for yamaha here, despite all the problems I've been seeing with these "B" suffix boxs they are a great motor, I don't want people to think I'm just on here to bag them. I have 2 yammys, and one of them is a F100 MY06, never missed a beat and we have hit more than our fair share of rocks, sand bars, logs, and the occasional crocodile over the years, and my leg has runs full syn oil for years now. No problems what so ever. So I'm at a loss as to what is going on with these boxs, remember at the beginning I also wrote that this same customer traded hi 3x F100's in for the new ones, in running the old ones for 3yrs he only ever did 1 LU.

I have also seen a couple of other customers motors with the "B" LU's and when the oil was drained from the box it didn't look crash hot. So I'm a little half expecting to get a call from them in the future with dramas.

Thanks for all the replys so far, I try to get all my facts correct but am the first to admit I don't know everything, it's why I like to get feedback from others in the field as well.

Cheers

[madharchod]

this is the problem here in Australia every Joe blog is a backyard mechanic who understands all outboard and starts operating their business as a outboard service agent in fact what they are is real motor car mechanics
you have to do special course for outboard to be servicing outboards and have factory training to deal with these motors as technology is advancing very fast to keep pace with as every year we are getting new electronic components added to motors which are made with obsolescence so you must be really up to date to fix or service these motors mate

[madharchod]

if it aint hypoid oil as specified in the manuals then you will have problems
i suppose you dont get them up north yeah mate

[rodbolt17]

I am NOT a petro chemical engineer.
that's why I asked the Japanese engineer the question when I was at school in Kennasaw Ga,yamahas north American HQ, a few years back.
that and I personally saw what syn gear lube can do to the fwd gear bushing on an F50.
no other damage other than it peeled the bushing out.

but I did ask why do we have to stock and use 2 types of oil and that was the reply from a Yamaha factory engineer,not a tech rep but an actuall engineer.

this poor old F50tlrb gets DOGGED.
it comes out of the water about once a year,more if we get hurricanes.
that's why I tried syn GL5.
it worked until it did not.
so far I have put two cyl heads on this motor and 1 gearbox.
I gave the old man this motor about 2006 and when its not crabbing its running nets so it runs most the year.

don't even get me started on those 4 stupid pencil zincs in the head or the 1 in the ex cover.
but I can tell you the symptoms when they break off and start drifting about the cooling system.

[boscoe99]

It is my understanding that GL5 gear oil (mineral or synthetic) has additives that are corrosive to the yellow metals that may be used within the lower unit.

GL4 (mineral or synthetic) does not have these additives.

The only Yam models that specify the use of GL5 gear oil are the F350, the V8 F300 and the Offshore F225/F250/300. (Highly loaded gears within the lower unit).

The SHO VF200/VF225/VF250 can use GL5 oil as an alternative.

Apparently the models that allow for the use of GL5 gear oil do not have any "yellow" metals used within the lower unit. Other Yams apparently might.

So, just follow the owner's manual and service manual GL and SAE requirements, whatever they may be, and life will be good. Synthetic or non-synthetic does not enter into the equation.

Here is what is posted at Mobil's website

Question:
Does Mobil 1 Synthetic Gear Lube Corrode Yellow Metals?
Is Mobil 1 Synthetic Gear Lube LS 75W-90 gear oil OK to run in Harley Transmissions? The big buzz on the internet chat rooms is that it corrodes "yellow" metals, such as brass and copper. Is this true? Please answer THIS question.
-- Michael Carravetta, Janesville, WI
Answer:
Unless the transmission specifically recommends an API GL-5 fluid for your transmission, it should not be used. GL-5 gear oils are designed for gears that require a high level of EP (Extreme Pressure) additives to protect gear teeth under extreme stress. Unfortunately, these same additives can be very aggressive toward “yellow metals “and are generally not recommended where copper, brass and bronze components are used.

[AusGeorge]

Hi Rodbolt
Yea those F50& F60 just go forever, great little engine.
I can understand Yamaha's statement about the GL5 Vs the GL4 in terms of the bushing, but the F80-100's LUs don't have bronze busing so I don't think it's for any of those reasons, did they hint at any other reason for not using synthetic?
We are very careful as to what grades of oils we use, as we have had to do major rebuild for customers that have failed to use the correct oil. So any info that has come direct from the manufacture is greatly appreciated.
Bosco, thanks for adding. It's always interesting to see major oil companies chiming in with tech advice, if they write it they have to back it up so always interesting reads

On another note, as interesting as the discussion is getting it's sort of getting away from my original post. We are about to strip all five boxs so I'll try and get out there with a camera an post some pics of the gears for you.
Cheers guys