Driveshaft won’t engage powerhead

[99yam40]

I would like to see pics of the crank splines and the drive shaft.

I wonder if Yamaha would have anything to say about this since it is only 4 months out of warranty

[rodbolt17]

I have seen a few driveshafts stuck in the crank due to excessive maint but have never seen the splines fail.

[Hamboat Captham]

I’ve never seen splines fail either and I’ve seen motors from the 60’s still going. Sure you’ll never get the shafts apart easy in those now!! I’ll get some pictures, that crank is stripped almost clean, driveshaft has you’re standard thrust marks and a little scuffing from spinning in the crank, but still serviceable, still has factory cross cuts on the splines.

Its only a 1 year warranty on their smaller motors the dealer here said, thought it was 3 years on all from Yamaha?? Conveniently for them they can’t find the service records !!


I thought about fixing it, machining out the end of the snout and pressing in splined sleeve. I was thinking crank defective too, first thing my buddies yam guy said as well yesterday when we got him. “Good news driveshaft sounds good, bad news sounds like a defective crank”. If this was a bigger motor I sure would be sore about it. Guaranteed I make stink with the regional reps and all

[boscoe99]

I’ve never seen splines fail either and I’ve seen motors from the 60’s still going. Sure you’ll never get the shafts apart easy in those now!! I’ll get some pictures, that crank is stripped almost clean, driveshaft has you’re standard thrust marks and a little scuffing from spinning in the crank, but still serviceable, still has factory cross cuts on the splines.

Its only a 1 year warranty on their smaller motors the dealer here said, thought it was 3 years on all from Yamaha?? Conveniently for them they can’t find the service records !!


I thought about fixing it, machining out the end of the snout and pressing in splined sleeve. I was thinking crank defective too, first thing my buddies yam guy said as well yesterday when we got him. “Good news driveshaft sounds good, bad news sounds like a defective crank”. If this was a bigger motor I sure would be sore about it. Guaranteed I make stink with the regional reps and all

Where is "here"? What is the complete engine ID?

If sold for commercial use then the warranty would have been for but one year.

[Hamboat Captham]

Ah makes sense, ya the guy had commercial, you need that to sell fish here

[99yam40]

Ah makes sense, ya the guy had commercial, you need that to sell fish here

we still do not know where you and the motor are located or what the motor ID is.
can yu give us that info?

from what you have said a commercial fisher sold you a motor that was just out of a 1 year warranty for a good price.
that to me means he knew something was going bad and wanted to get rid of a almost new motor.

if the price was low enough then you could have suspected something was not right with the motor

[boscoe99]

we still do not know where you and the motor are located or what the motor ID is.
can yu give us that info?

from what you have said a commercial fisher sold you a motor that was just out of a 1 year warranty for a good price.
that to me means he knew something was going bad and wanted to get rid of a almost new motor.

if the price was low enough then you could have suspected something was not right with the motor

I suspect that the 2015 commercial motor was two years plus out of warranty.

People think the model name and engine ID's are top secret. Shhhh. Can't let it be disclosed. Keeps things interesting around here.

[zenoahphobic]

No matter the history or how the OP obtained the motor, how did this happen?

Yes older than thought, commercial probably means used a lot of hours, but what abuse (if any) could contribute?

I can only think that the leg is not the original at all; that the original suffered some terrible injury that may have dead stopped the engine at full revs (or higher revs).
Slammed into gear at high revs, smashing the gears etc full lockup, then locked shaft " machining out" the crank splines because the crank wanted to keep turning because it had high inertia and a ham fisted monkey on the throttle ......PERHAPS!

[FabricGATOR]

No matter the history or how the OP obtained the motor, how did this happen?

Yes older than thought, commercial probably means used a lot of hours, but what abuse (if any) could contribute?

I can only think that the leg is not the original at all; that the original suffered some terrible injury that may have dead stopped the engine at full revs (or higher revs).
Slammed into gear at high revs, smashing the gears etc full lockup, then locked shaft " machining out" the crank splines because the crank wanted to keep turning because it had high inertia and a ham fisted monkey on the throttle ......PERHAPS!

In your stellar seamanship scenario described above, could the drive shaft have bent and then the skipper continued to run the engine while ignoring the vibration? I would imagine that could mangle the crankshaft and waller out the spline... That is the only idea how this could have happened and not be a Yamaha quality issue.

Then replaced the lower and sold a "great looking" engine (with hidden damage).
Someone is taking the true story to Davy Jones' locker....

[FabricGATOR]

Iwannasee Iwannasee.... pictures

or it didn't happen.

[zenoahphobic]

In your stellar seamanship scenario described above, could the drive shaft have bent and then the skipper continued to run the engine while ignoring the vibration? I would imagine that could mangle the crankshaft and waller out the spline... That is the only idea how this could have happened and not be a Yamaha quality issue.

Then replaced the lower and sold a "great looking" engine (with hidden damage).
Someone is taking the true story to Davy Jones' locker....

Say somehow the shaft got bent (used to lever a piece of concrete out of the way at the boat ramp?) , that itself very difficult to do, it would be extremely unlikely to get that shaft to engage when refitting the lower leg.

In any case if it was fitted bent, I don't think the change in play or fit on the splines, nor the vibration could have produced enough hammering energy to do that damage. The shaft if anything would be tighter, the connection is not like gear on gear changing by rotation.

Sorry, I've just reread what you wrote and meant, that the shaft bent by abuse and then gradually destroyed the splines in situ. Unlikely but possible I suppose, depending on the hardness of the shaft, torsional force could have twisted it, but they usually would shear.

[Masonmobilemarine]

Sorry guys been busy.

My motor was a 2003 F225.

I actually have a 2005 F225 stripped down as well. I'll show you picture of each crankshaft so you can see the difference.

Also should note, this engine completely ATE one of the side thrust bearings. As in, I opened the block all the way to a bare block....and there was an entire thrust washer/bearing just gone. Crank had been slamming into the side walls for awhile .

[Masonmobilemarine]

[99yam40]

what does this have to do with the 2015 T9.9 this thread is about?

[Masonmobilemarine]

No idea about the crank, Boscoe should know and will post...

A NEW crank is about $400... https://www.boats.net/catalog/yamaha...nkshaft-piston

First I've heard of those crank splines "going away"....

Mason, was your above stripped engine a small engine or?


Hamboat, probably be a waste of time, but worth a try.
Contact the seller and see about at least a partial refund. With NO remnants of the splines (per post #1) the issue would have known by the seller (as debris WAS CLEANED AWAY when sold to you)and NOT disclosed...

Here ya go 99yam