Gear drive shaft stuck to crankshaft

[Conorthesailor]

Hi

I'm looking for a photo shot from the Yamaha 15hp 2 stroke (2009) service manual (or a soft copy even better) which might show me how to disassemble the lower gear drive shaft.

The Engine flywheel was jammed solid but now it moves a few inches. But that's all. However we have checked and the piston is ok. Now we are trying to remove the lower gear which normally comes out. the problem seems to be the lower gear drive shaft is stuck to the crankshaft.

The owners manual supplied is quite useless. All of this happened after just 2-3 months of no usage. But she was sitting in the hot sun on the back of my sailboat in Singapore.

Grateful for the service manual.

[rodbolt17]

with NORMAL maint this NEVER happens which is why its NOT covered in any service or owners manual.
its also why I wont work on blow boat motors.

the 9.9 and 15 Yamaha can do two things.
one is stick the actual shaft splines to the crank splines.
2 is the crankshaft seal carrier can corrode/swell and lock the driveshaft.

if its 1 turn the motor upside down and soak for a few days with oil of wintergreen.
if its 2 then use oak wedges,steel if your careful, and while tapping the wedges in turn the flywheel.

its amazing why blowboaters wont spend 2 bucks on grease yet get mad cause it stuck. .

[99yam40]

Hi

I'm looking for a photo shot from the Yamaha 15hp 2 stroke (2009) service manual (or a soft copy even better) which might show me how to disassemble the lower gear drive shaft.

The Engine flywheel was jammed solid but now it moves a few inches. But that's all. However we have checked and the piston is ok. Now we are trying to remove the lower gear which normally comes out. the problem seems to be the lower gear drive shaft is stuck to the crankshaft.

The owners manual supplied is quite useless. All of this happened after just 2-3 months of no usage. But she was sitting in the hot sun on the back of my sailboat in Singapore.

Grateful for the service manual.

If you cannot drop the lower unit and remove the water pump housing etc the drive shaft cannot be removed from the lower unit so you are stuck with Rods suggestions.

As far as manuals go, look up your services manuals part # and then do a search on the web to see what you can find

[rodbolt17]

not gonna find anything in a service manual on how to remove a neglected part.

look at the parts diagram.
see the engine lower oil (crankshaft) seal holder.
see how it has a tube about 4" long that the drive shaft passes through.
corrosion can and will swell that tube so tight it locks the shaft.

IF the splines are not rusted together and it JUST the seal carrier has swollen then you can rotate the flywheel while wedging the lower away from the midsection and "unthread" it.

not my first rodeo with it.

[boscoe99]

I just fought a battle with the tub bearing seal in my washing machine. Corrosion was the culprit. You have to pull the tub out to gain access to the seal. Damn near could not get the tub off. Finally took the tact that the tub is coming off, or the washer will be irreparably damaged, which at the time either was acceptable. Either I was going to fix my old washer or I would be buying a new one. Did not matter which. But success.

Now looking at a manual or watching a you tube video regarding the process, of course they show the tub simply and easily sliding up and off of the bearing. And they were in a large open room instead of being in a tight and cramped laundry room.

[Conorthesailor]

Thanks a lot .... From the blow-boater which is a new term to me!

Will report back.

[TownsendsFJR1300]

From the blow-boater which is a new term to me!

I learned it here as well!!!

Good luck

[99yam40]

wind blown boat owners do not do a lot of maintenance on their motors usually as it is not their main source of getting around

[rodbolt17]

blowboaters.
wind is free and everything else outta be .
but powerboaters do it as well.
wait ten years until the water pump fails.
then a piston is smoked and the crank and drive splines are married and it goes south from there.

[bajakeith]

sailers & others

I don't work on sail boats any more !! Why ?? for the simple fact that the wind is FREE and They don't want to maintain,service anything that cost money and takes skill,and I have sailed from Baja to the sorrocco's thru the hawii to steward Alaska...So I can say without debate I am a pwr boater with time on a rag boat..BUT after over 35 years in the boat repair biz I can say..."I have found sail boaters don't,,Do Not take care of their motor's.. and then expect to get it fixed for 20 buck's.....lazy bum's !!