Cutless bearing wear rule of thumb

[ArtJ]

Hi Guys

What is the generally agreed rule of thumb on checking for Cutless bearing wear?

I recall something like a 1/8 inch or a 1/16 inch max wobble max shaken

Please let me know what the concensus is for measurimg the max allowable
wear?

Regards

Art

[msmith10]

At 1/16 I'd be planning it. At 1/8 I'd do it.
A little bit depends on your haulout schedule. I have to haul yearly so there's more opportunity to change it at my discretion. If you're in all year I'd probably change sooner if I was hauling out for something else to avoid a haulout just for that

[ArtJ]

Thanks Mark

You have confirmed my recollections. My boat is on the hard in Boston every
winter. Just trying to stay on top of a issue a little ahead of time.

Regards

Art

[hanleyclifford]

Hi Art - Before you remove that cutless bearing take a picture of it from dead astern - analysis will reveal a lot about how the shaft is running and engine alignment. Regards, Hanley

[ArtJ]

Hi Hanley

Thanks for the response. I believe the shaft is well aligned, at least from
viewing the shaft rotate exiting the engine when running.. I also believe that the wear may still only be a 1/16 or so. (BTW, Is this measured as "unipolar from the
center rest position, or from either extreme limit.

Analogy would be the difference crest to trough depth of a wave vs it's
average calm water position to crest or trough. There is a 2 to 1 difference
in the measuring points. At any rate, I am assuming the full side to side
wobble distance to be the correct one.

I repacked the stuffing box last season with 3 staggered rings. Possibly
could have used 4.


Thanks and Regards

Art

[hanleyclifford]

Art - The reason for my response is that I have experienced a true running shaft viewed from the back of the engine when it was not true in the cutless. Apparently, the shaft can "rebore" the cutless over time and run very well, within limits , of course. A new cutless offers the opportunity for a new alignment which will reduce or eliminate the "reaming" of the cutless, if you will. Observing the old cutless with the shaft removed can be very revealing. Regards, Hanley

[CalebD]

I'm not sure what metal your shaft is made from but when we began the process to replace our cutlass we found that our 43 year old bronze shaft was badly worn at the cutless bearing. The bearing itself was not so bad (but of unknown age) but the shaft was badly scored which created the 1/16" or so play at the prop end.
After cutting the old bronze shaft in half with a Sawzall we now have a new cutless bearing installed and a new SS shaft with reworked prop and flange to install come a warm day.
The cutless bearing is not always the only problem.

[ArtJ]

Thanks guys

I do have a bronze shaft. I had the cutless replaced about eleven years ago.

Good points about shaft wear and wear inside the cutless itself.

I know this has been covered previously, but how is the shaft removed?

The coupling must be split right? , then does the shaft get removed out
the prop end? Actually, as I think about it, can the shaft be upbolted at
the coupling end without splitting the coupling?
OTherwise, I would think that the coupling would have to be removed from
the engine tailshaft because how else would you get the coupling or half
coupling around sideways past the rest of the coupling. ]
I am also assuming that the rubber boot should be replaced as well.

Thanks and best Regards

Comments Appreciated


Art

[msmith10]

You either have to remove the coupling or the prop then just slide the shaft out. In many cases there will not be enough clearance to slide it out forward past the engine, so usually you'll be removing the coupling then sliding it out aft. Note that I'm talking about the prop shaft coupling, not the reversing gear output flange- that will stay in place.
There's been quite a few posts on the trials and tribulations of getting the prop shaft coupler off the shaft. This is a PITA at best, and impossible in many cases. You can try pressing it off- there are lots of posts describing this procedure. Many times it's easier to cut the shaft.
A few other points- if you removed the coupler to pull the shaft, take it to a shop and have the coupler trued to the shaft before reinstalling it. Even if it was true before you removed it, there's a good chance it won't be by the time you're done. If it isn't true when you put it back on, it's impossible to align the shaft.
Replace the rubber boot? I assume you're talking about the shaft log hose- it goes between the shaft log (the glass tube that's part of the hull where the shaft exits) and the stuffing box. If it's brittle, cracked, or deformed, yes, replace it. If you think it's been a long time since it was done, do it. You can't do this job without hauling the boat, and if the rubber tube breaks, the boat will sink. I'm doing this job this spring.

[ArtJ]

Thanks Mark

I am assuming, and if memory serves me correct/ly, that the shaft is held on
to the coupler by a single threaded bolt. Is this correct? Theoretically,
if one removes this bolt, the shaft should pull out of the coupler?
Also how does one ensure alignment when the cutlass is replaced between
the cutlass, shaft, coupler and engine?

Anyone have pictures of this process?

Thanks and regards

[msmith10]

There have been lots of posts on this and you may be able to find pics but I don't know where they are offhand. Yes, there is a set screw to lock the coupling to the shaft (along with a keyway) but I doubt that this really contributes on any boat that's been in the water for any length of time. You have to remove it, of course, but don't expect the coupling to slide off the shaft after you've done that. I recently removed my coupling and it was incredibly tight- that's after just about 5 years in fresh water only with no visible corrosion and a stainless steel shaft. Pressing the coupling off the shaft inside the boat has been discussed several times recently and if you search for that, you'll find descriptions on how to. Basically, you loosen the shaft coupling/output flange joint, put a suitably sized object (socket, stack of washers or coins, etc) between the output flange and end of the prop shaft that's coming through the shaft flange, bolt it back together and tighten the bolts evenly and slowly. Use lots of PB blaster before and during. Be aware that you can apply enough force during this process to trash your output flange. Because of that, and the frustration factor, some guys just cut the shaft. If your shaft is significantly worn or scored at the stuffing box or cutless bearing, you might as well cut the shaft and save the work.
As far as lining everything up, hopefully when your boat was built, the shaft log was laid up so that it lines up with your cutlass bearing. Replace the shaft and holding it (you can wire it up or fashion some wood blocking) so that the shaft is centered in the shaft log-- that's your alignment. Now you move the engine to the shaft and coupling.

[ArtJ]

Thanks for the great information.

I went to the boat this morning and looked at the play at the prop end of
the shaft. There was virtually none side to side and less than a sixteenth
vertically. So it looks as though I can hold off on this repair for the time
being.

All the responses are appreciated. I will be much more prepared when
the task needs to be done

Thanks to all

Appreciated

Art

[msmith10]

If it ain't broke don't fix it. There's probably plenty of other stuff that needs fixing.

[romantic comedy]

Hi Art,

seems we are following each other. I have changed my cutlas twice. I also remove my shaft each year with the boat in the water. Yes strange. I seperate the coupling from the shaft and a diver pulles it out with the prop on it. I do this to clean the prop, then replace the shaft. It is the best way to clean the prop in the water. Since my boat stays in the water year round.

Yes you need to remove the side set screw. For your coupling it may take a lot of effort, I am guessing. My coupling is probably the same as yours, 3 bolts. You can make a puller pretty easy. Just take the bolts out and make a pattern.

When removing the cutlass, use a home made puller. Dont let the marina cut it out. Take a threaded rod, half inch by 18 inches or 2 feet, I guess. Find something like a socket that will fit in the shaft tube over the threaded rod and hang up on the cutlass. Make a 2X4 or something with a hole to pass the rod thru. Put it on the rod from the outside. Space it of f the boat and crank on the nut. It comes right out, no matter how it was glued in.

BTW, you have to remove 2 set screws on either side of the cutlass.

I have found that the play is hard to determine by moving the shaft. I was not going to replace the cutlass because it was tight. Then I had to remove the shaft anyway. So i found that the cutlass was very worn and needed renewing.

I would replace it if you are thinking about it.