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

[TownsendsFJR1300]

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. Ok, that's fine.. Your likely re-placing it anyway..

pulling on the shaft is a lot less damaging than a sharp blow. Agreed, posted that above..
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

I've never read / heard of the power head splines being rusted away (useless), NEVER.. RB or anyone else?

Brake cleaner and clean shaft (maybe lightly coated with grease) with no rust will do the same thing. Getting it out IS the hard part..

MUCH EASIER / faster than yanking the power head with the same results.

[DennisG01]

Yes, definitely agree on using quality grease. I've been using Merc's Extreme grease for a while now and it's really nice. I'm sure the Yamaha stuff is good, too - I have easy access to the Merc stuff, though. And, yes... not too much of it and NOT on top of the driveshaft tip.

I was wondering about the "gap" for cutting, too. And also about cutting through the actual water pump, but I suppose that's a small price to pay... and you might be replacing that (and the housing/kit), anyways.

I'm going to keep trying to get it unstuck, but will also do as others have mentioned... don't do anything drastic, yet. I'll see if I can see things well enough to get an approximate location on where that crank/drive shaft connection point it... just so I can cut a good access hole the first time. Maybe I can also find a picture of how far the crankshaft extends below the powerhead mounting points, as that would also be a good way to measure for an access hole cut.

EDIT: So far, every picture I find of a powerhead (with crank installed) appears to have had the picture taken with the powerhead sitting flat on a table/workbench/etc. Does that mean that the bottom end of the crank DOES NOT extend past the powerhead mounting base? That seems to be what I gather by looking at the pictures, anyways. If so, that helps to answer my initial question (along with the suggestion to look into the gap).

[rodbolt17]

why o why are you so insistant on cutting holes????
simply sawzall it just above the tiller area. yep it has been done on two and 4 strokes cause I have done it.
look at the opening just above the tiller,see that pipe stinkg down?
that is the drive shaft.
either way the powerhead comes off. either way you buy a shaft. this way your not fixing a case with a hole or two in it.
I have seen pretty much ALL brands stick a shaft due to lack of maint.
had one did it in 6 months/550 hours.

[boscoe99]

I am not suggesting it but someone (anyone) might want to let the motor run at an idle and then hold (carefully) a hack saw blade against the rotating drive shaft. Like a cutting tool against a steel shaft being turned on a lathe. See what happens. I am not responsible if someone gets hurt doing this.

I would not be drilling/cutting any holes either.

But before cutting the drive shaft I would do my best to get some penetrating oil to the drive shaft/crank shaft junction and see if it will migrate into the connection. I might even remove the motor and turn it upside down to get penetrating oil into the crank shaft bore. Then I would impact hammer the hell out of the drive shaft with the lower unit unbolted and the motor running at idle first. I get lucky in a blue moon or two.

[DennisG01]

I'm not against cutting the driveshaft - in fact, I have that in the back of my head as where this is going to end up. But in my eyes, cutting a hole in the case is the least intrusive, and least expensive, "possible" fix. Meaning, it's worth it to me to give it a shot, first. The hole in the case doesn't bother me one bit as I can patch that easily enough... actually, that should be a piece of cake compared to the gut job I did to the boat's ****pit floor, stringers and bulkhead. If I was paying someone to do the work, cutting would likely be the easiest/cheapest route. But for now, it's just my labor.

Just so I'm clear... "Tiller area"... means the little arm that the hydraulic steering arm attaches to? As in a "tiller arm" from a littel kicker motor?

Boscoe... do you think there is enough room to get an impact tool in there? I'm envisioning that air chisel with a long extension. BUT... if the tool buggers up driveshaft, will that prevent the driveshaft from sliding out? In other words, is there any tight-fitting "guide" of some type further down the driveshaft that the driveshaft goes through? I'm not sure if I'm explaining my thought well enough, there...

I've got my spare engine stored about 45 minutes from my house here in PA (one bad cylinder). I'll try and get over there in the next few days and look at everything close up to get a better idea of the ways you guys are saying to see and/or cut the driveshaft.

[boscoe99]

Speaking from a fading memory I think there is clearance to get an impact tool in there. I would not be so aggressive as to bugger the drive shaft up however. Just keep hammering for five or more minutes and see if you see the start of any movement. You gotta be thinking about not damaging the crank shaft also but I think that is a low low possibility.

There is an upper casing in the mid-section but that can be removed if necessary to get the drive shaft down and out, if it comes to that.

[DennisG01]

Speaking from a fading memory I think there is clearance to get an impact tool in there. I would not be so aggressive as to bugger the drive shaft up however. Just keep hammering for five or more minutes and see if you see the start of any movement. You gotta be thinking about not damaging the crank shaft also but I think that is a low low possibility.

There is an upper casing in the mid-section but that can be removed if necessary to get the drive shaft down and out, if it comes to that.

Good point about the crankshaft.

Upper casing... it's funny, when I first started down this road I was so happy that that piece was removable as it would give me good access to the driveshaft/crankshaft union ... until I looked in the Service Manual and saw that in order to get to that union, I had to remove the lower unit to remove the upper casing. So... to "unstick" a driveshaft, I would first have to remove the lower unit.... Sort of a moot point, from this issue's standpoint, anyways!

[TownsendsFJR1300]

I'd bet running it, bolts very loose and shifting, some rev's(vibrations), letting gravity help you, you have a good chance of it breaking loose. You know you greased it, what 3 years ago?

And, you have absolutely NOTHING to loose trying this, just some time. I don't think I'd be hammering anything in there.

[DennisG01]

I'd bet running it, bolts very loose and shifting, some rev's(vibrations), letting gravity help you, you have a good chance of it breaking loose. You know you greased it, what 3 years ago?

I'm keeping my fingers crossed!

I've had the boat for close to 3 years now. I'm not sure when it was greased last. All I can say is that I have never greased it. The previous owner was a trailer boater and always flushed it... hopefully that helps at least a little

[panasonic]

Had a 20 mercury with same problem.Tried to change WP and LU would not come off. Ran it a few more years until the pump finally quit.

Tried wedges, no go. Hung the engine upside down from rafters, drilled a small hole in the leg and started spraying loosening oil on the shaft so it would run down the shaft. Ended up drilling a hole down thru a joist in garage floor installing a eye bolt and hooking up a come along to the LU to the rafters. Tow strap wrapped around flywheel hooked to the floor. Put pressure on the come along and left it there all one winter.

Every so often I would put another click on the come along hoping it would give way. Started bowing floor up with so much pressure.No go.

Cut shaft off through the hole in leg I had made...finally apart. drilled and tapped hole in shaft and slide hammered it out. Splines on the crank where pretty much gone. All for nothing.

Sold the engine for parts.

I was told engine was serviced regular and it was in excellent shape otherwise. Impeller was like hard plastic...never ever had been changed.

[ausnoelm]

This is where the word "service" gets hazy, to some, a service is spraying some stuff around, then wiping it off and checking spark plugs, to others you need a service when somethings wrong, when in fact, that's a repair, not a service, to others who know, a service is thorough routine maintenance that ensures your motor runs within specified parameters with correct lubricants.

[pstephens46]

I always thought the alarms were to notify you it is time for service?

[TownsendsFJR1300]

Had a 20 mercury with same problem.Tried to change WP and LU would not come off. Ran it a few more years until the pump finally quit.

Tried wedges, no go. Hung the engine upside down from rafters, drilled a small hole in the leg and started spraying loosening oil on the shaft so it would run down the shaft. Ended up drilling a hole down thru a joist in garage floor installing a eye bolt and hooking up a come along to the LU to the rafters. Tow strap wrapped around flywheel hooked to the floor. Put pressure on the come along and left it there all one winter.

Every so often I would put another click on the come along hoping it would give way. Started bowing floor up with so much pressure.No go.

Cut shaft off through the hole in leg I had made...finally apart. drilled and tapped hole in shaft and slide hammered it out. Splines on the crank where pretty much gone. All for nothing.

Sold the engine for parts.

I was told engine was serviced regular and it was in excellent shape otherwise. Impeller was like hard plastic...never ever had been changed.

That sucks ^^^. I'm surprised the splines rusted away.. I'd think the metal was somewhat hardened, apparently not much if a saw-zall will cut it off..

I'm fortunate enough to NOT have to buy a used engine and bright enough to be able to grease, do WP's, etc, so I know what I'm dealing with...


Dennis, If you've had it for 3 years (no re-grease), and who knows when it's been serviced (for real), sounds like you may be in the same boat as Panasonic...

I think I'd try the previous run / vibrate procedure and if it comes off, great. If not, button it up until you HAVE TO CUT if off and hope the crank splines are salvageable..

[TownsendsFJR1300]

I always thought the alarms were to notify you it is time for service?

They tell you when it's TOO LATE...

[rodbolt17]

folks it is called preventative maint. Yamaha outlines the basic procedure. from there folks like me with 40+ years of dealing with machines takes over.
you owned it 3 years and did NOTHING.
I call it.
FIRST thing you do when you buy a machine ,actually BEFORE you buy it, is have a PROFFESIONAL look at it.
not a cousin,not an aunt, not a brother-in-law who had a sister who's ex huspand fixed a tractor on a farm once.
PM is way cheaper than repairs.
that drive shaft is about 600 bucks on the counter.