Where to drill casing to access driveshaft/crank? OX66 250HP

[DennisG01]

I guess what it all amounts to is, the shaft is stuck, anything is worth a try to get it off, whether that is wedges, starting motor, hitting with air tools, bolts in or out or anything else, it's worth a try, failing that, it's a cut the shaft job, cutting is relatively simple, but the work to replace it is considerable, of course there is the easy option of not removing it at all until it really needs to come off!

Yup, that's pretty much where I'm at. Right now everything is working just fine and no signs of overheat or excessive salt build-up anywhere inside. It's only run in pretty clean water - usually deep water - no sand.

[DennisG01]

Based on his previous threads/posts, the shaft has been "stuck" for some time. It's probably weighing on his mind....Impeller etc....I don't envy his situation.

Bingo (and good memory!). Right now it's a "want to get it off" thing... not yet a "need to get it off" thing. But, of course, I'd like to do it BEFORE it becomes a "need".

So if I can get at the driveshaft/crankshaft union point and spray it with "whatever" (or create that dam) over the course of a few weeks, then try to remove it again... MAYBE I'll get lucky!

[pstephens46]

Bingo (and good memory!). Right now it's a "want to get it off" thing... not yet a "need to get it off" thing. But, of course, I'd like to do it BEFORE it becomes a "need".

So if I can get at the driveshaft/crankshaft union point and spray it with "whatever" (or create that dam) over the course of a few weeks, then try to remove it again... MAYBE I'll get lucky!

Check this dude out at the link....

https://www.instagram.com/p/Bgzdrlvhc63/?hl=en

hope it works....prop hammer not enough? Go with the flywheel hammer!

back up a couple pics and view the before cutting shaft, etc. Apparently a Master Tech too.

[panasonic]

Can only see one picture...

[pstephens46]

Can only see one picture...

Can you see the little white arrows on the left and right on the first picture? Maybe 7-8 pics to scroll through? Could take a few secs to load.

the guys Instagram, in general, is interesting.

[panasonic]

Only get picture with the guys watch..
lol Do you have to be part of instagram?

[pstephens46]

Only get picture with the guys watch..
lol Do you have to be part of instagram?

Are we the only ones awake?

try this link.
https://www.instagram.com/strictlyyamaha/?hl=en

you will see the series.....

[rodbolt17]

you do realize that the crank has only one thrust bearing?
simply sawzall the shaft. remove the power head. remove the stub from the crank. replace the shaft, AFTER carefully measuring the original pinion to fwd gear back lash. continue boating. next time follow the service guide.
at this point if it is not overheating I would simply run it till I had to do it.

[DennisG01]

A prop and flywheel being used for weight... That's freakin' awesome! I love it!

Rodbolt... can you expand on what you mean by "the crank has only one thrust bearing"? Meaning, what is the importance of saying that? Is it a warning about not doing too much "slide hammer" work as it could damage something on the crank?

I had this engine for about 2-1/2 seasons before I decided to change the impeller - primarily just for good PM. Truth be told, I did not know these shafts corroded up so quickly. I am very familiar with Mercruisers and have worked on those for a few decades (although not fuul time professionally). I have NEVER had an issue pulling a lower unit on a Mercruiser - or at least not where I needed anything more than a swift kick to the lower unit to free it up. Of course, that's my ignorance for not finding out more about the Yamaha... but I just didn't think there'd be that much of a difference when it comes to "need" for the lower unit removal.

[TownsendsFJR1300]

Are we the only ones awake?

try this link.
https://www.instagram.com/strictlyyamaha/?hl=en

you will see the series.....

Worse case scenario, cut the shaft (IF possible as shown in the video) where the LU meets the mid section, then put a puller on that.

No smacking on the thrush bearing and NO power head removal...

Same as RB's method but half the work.
'

[TownsendsFJR1300]

I had this engine for about 2-1/2 seasons before I decided to change the impeller - primarily just for good PM. Truth be told, I did not know these shafts corroded up so quickly. I am very familiar with Mercruisers and have worked on those for a few decades (although not fuul time professionally). I have NEVER had an issue pulling a lower unit on a Mercruiser - or at least not where I needed anything more than a swift kick to the lower unit to free it up. Of course, that's my ignorance for not finding out more about the Yamaha... but I just didn't think there'd be that much of a difference when it comes to "need" for the lower unit removal.

The kind of grease you use CAN / WILL make a difference.

I use genuine Yamaha WATERPROOF GREASE and have gone as long as 3 seasons without any issues at the splines (or mid section bushing squeaking).

I know regular marine wheel bearing grease will NOT hold up for two months at the mid section bushing W/O squeaking. The Yamaha stuff, again 3 years no issues (light use I might add).

BTW, the thrush bearing keeps the crankshaft within certain spec's from moving up and down (or side to side auto applications). Hard impacts (as shown in the video) could damage that bearing. The thrush bearing isn't designed for those sideways loads / impacts.

[99yam40]

Worse case scenario, cut the shaft (IF possible as shown in the video) where the LU meets the mid section, then put a puller on that.

No smacking on the thrush bearing and NO power head removal...

Same as RB's method but half the work.
'

I do not see how you could get to the shaft at that location to cut it off so you could weld it.

and using a slide hammer device to pull the shaft stub will be pounding the thrust washer on the crank.

[pstephens46]

I do not see how you could get to the shaft at that location to cut it off so you could weld it.

and using a slide hammer device to pull the shaft stub will be pounding the thrust washer on the crank.

There are some other pics on that Instagram account showing how he got enough clearance to slip the blade in between lower and mid section.

This is obviously radical surgery and last ditch effort to remove the shaft. You would have to yank on it one way or another. Easier, IMO, with power head attached versus removed.

[TownsendsFJR1300]

I do not see how you could get to the shaft at that location to cut it off so you could weld it.

and using a slide hammer device to pull the shaft stub will be pounding the thrust washer on the crank.

I posted IF you had enough room (they did on that video), and I posted PULL the shaft, NOT hammer slide.

Also, if that shaft sticks out that far, it CAN be welded(as shown in that video). I'd weld two bolts to each side of that shaft and then use a puller rigged for the shaft and case.

I do weld and it would NOT be hard to do at all.. (on Pats second post/video does show the drive shaft welded to another piece of steel(IE-plenty of room)...

Basically what RB does BUT NO powerhead removal and no hammer slide..

To get that gap is the hard part... And, very likely, if you get that gap, those splines are already starting to loosen

[99yam40]

unless that motors is built way different than most I pulled apart ,
a small gap down there would require you to cut thru the water pump also

pulling on the shaft is a lot less damaging than a sharp blow.
and as Rodbolt said the spines in crank need to be cleaned up and inspected to make sure they are good enough to install a new shaft.
kind of hard to do that from there