[C320-list] Stuffing box nut replacement?

16 views
Skip to first unread message

pto...@4square.net

unread,
Mar 29, 2021, 3:10:27 PMMar 29
to C320...@catalina320.com
Just replacing the "stuff" in the stuffing box and discovered that the
packing nut doesn't want to thread back on.

Boat's on the hard.

It doesn't seem to be damaged and I cleaned it up with a hand wire brush.

The mating threads are fine as the locking nut goes over easily.

And no I haven't put a wrench to it (yet).



With my handy endoscope I can see that the threads at the start are corroded
a little. As I tighten it by hand it starts to grab then 'pops' back

I did use a sharp scribe to chase the threads and it cleaned them up and
tracked just fine.



So.. It look s like I'm gonna try to mark then unbolt the shaft to engine
coupler, remove the flange (soft mallet?) and the keyway and replace the nut
IF I can find one. I know I'm be 70% of the way to replace the whole
assembly but It's not needed.



So before I hit anything with a BFH, who got some advice for me?

Is the shaft coupler that easy to remove?



Pat



Pat Tormey
S/V Blue Skies
Newport RI



Troy Dunn

unread,
Mar 29, 2021, 3:29:25 PMMar 29
to C320...@catalina320.com
Don't hit the coupler with a hammer. You need to use a coupler puller.
Even then there is a chance you will bend the flange...if that happens you
may not be able to align the prop shaft to the engine. The fix for that
is a new shaft and coupler that has been faced to the shaft and then a
realignment of the engine which might snowball into needing new engine
mounts. If you can fix the stuffing box without pulling the coupler that
is ideal. If not...be prepared for the BOAT ride.

FWIW

Troy Dunn
Hull #514

Arthur Gates

unread,
Mar 29, 2021, 3:41:18 PMMar 29
to C320...@catalina320.com
Tap the stuffing farther in so more threads can get bites
Rollie #182

Sent from my iPhone

> On Mar 29, 2021, at 3:29 PM, Troy Dunn <troutw...@gmail.com> wrote:
>
> Don't hit the coupler with a hammer. You need to use a coupler puller.

Doug Treff

unread,
Mar 29, 2021, 3:53:48 PMMar 29
to c320...@lists.catalina320.com
I'll just add my $0.02 here regarding the BFH technique: DON'T DO IT!

To put all this back together and do a proper alignment, you'll be trying to align the coupling faces within .001" across the face. Do you really want to run the risk of banging on that flange with a hammer if you need to realign it later? Not to mention the danger of bending the prop shaft.

Use a puller or hire a professional.

I agree with Arthur, it could be that the stuffing is keeping the threads from grabbing. How many rows of stuffing did you put in? Maybe consider doing it one row at a time, compressing it with the nut, then add another row.

I'd bet money that is the issue and not the threads.

--
Doug Treff
do...@treff.us

RONALD HODEL

unread,
Mar 29, 2021, 4:14:58 PMMar 29
to C320...@catalina320.com, c320...@lists.catalina320.com
I’m with Doug on this. It’s the least expensive option for starters
Ron
#1070 Lokomaikai

Sent from my iPhone

> On Mar 29, 2021, at 1:53 PM, Doug Treff <do...@treff.us> wrote:
>
> I'll just add my $0.02 here regarding the BFH technique: DON'T DO IT!

Ken

unread,
Mar 29, 2021, 4:31:44 PMMar 29
to C320...@catalina320.com, c320...@lists.catalina320.com
Three layers of gfo took up a lot of room in my box. I had the same issue but once I got it to bite and compressed it a bit, it stayed. All has been well for years!
I do like the suggestion to compressing it a bit before the last layer. Keep track of the seam locations though.
Ken
MoonDancer
1089

Sent from my iPhone

> On Mar 29, 2021, at 4:15 PM, RONALD HODEL <ronan...@me.com> wrote:
>
> I’m with Doug on this. It’s the least expensive option for starters

pto...@4square.net

unread,
Mar 29, 2021, 4:55:30 PMMar 29
to C320...@catalina320.com
It will not hand start without any stuffing! So it's definitely the threads.


No I'm not hitting anything with a hammer. I was thinking AFTER I disconnect from the motor the key'd couple shouldn't be too tight a fit.
But I'll use a puller if it comes to that.

I am hoping hat I can get past the first full turn by hand when there will be plenty of thread engagement.

thanks

Jeff Smith

unread,
Mar 29, 2021, 5:04:37 PMMar 29
to C320...@catalina320.com
I am not versed on the stuffing box but I think the concept is the propeller shaft extends through the stuffing box, which contains the packing material, and then there is a jam nut and a packing nut that you use to tighten everything. Is it possible to take the propeller shaft loose from the coupler (leave the coupler attached to the engine), retract the propeller shaft enough so that you can re-threat the stuffing box (or replace it with one from CD)? You could borrow the Association tool and change your cutless bearing while you are at it (if it has not been replaced in awhile).

Again, I have a dripless so this may be worthless advice. But I would try this, or something like it, before I removed the coupler from the transmission/engine and had to worry about alignment issues.

Jeff
’94, #121

Dave Hupe

unread,
Mar 29, 2021, 6:13:07 PMMar 29
to C320...@catalina320.com
Jeff- The packing  material is in the large packing nut, not in the "stuffing box".  You loosen the thin lock nut and then completely unthread the large nut and slide it toward the engine while still on the shaft.  You clean the old packing out of the inside of the large nut (using like dentist picks), clean up all the threads, insert new rings of packing (usually 3 rings) and then thread the large packing nut back on to compress the packing material against the forward end of the packing box and the shaft.  Then the lock nut gets tightened.  You don't crank the large nut down very tight to start.  You set it and run the engine/shaft for a while, then come back to snug it to the point where it drips only a little while motoring, but doesn't drip when sitting idle.
Pat -  This really sounds like a simple burr on a beginning thread (either the female threads of the nut or the male threads on the stuffing box end.  I would try cleaning the threads again, keep trying to get it started by hand,  and "persuade" it very carefully with a wrench.  From what you have described, I really don't think you will need to do any of the other much more involved options. 
Dave Hupe
1994 C320 (#32)
Holland, MI 


pto...@4square.net

unread,
Mar 29, 2021, 6:39:55 PMMar 29
to C320...@catalina320.com
Dave, I think your are right.
I'll keep working the internal nut threads.
I'll try again tomorrow. I tend to lose patience when something so simple turns to sh$t 😉
thanks
Pat

Pat Tormey
S/V Blue Skies
Newport RI

Reply all
Reply to author
Forward
0 new messages