Stuffing box heat

[bcguy]

I am having problems with my stuffing box. No matter what goes in there it's a problem. I recently tried the new gfo goretex which heated up to steaming... then flax same thing. Even despite loosening the cap so water was dripping steadily. I also tried installing a grease nipple in the stern tube and pumping full of grease. Eventually the grease worked it's way out and into the bilge (quite a mess) which I completely cleaned out. The shaft is new so it is not bent. This leaves faulty stuffing box, problems in the cutlass bearing or the connecting hose from the stuffing box to the stern tube. Just wondering what one would like for to see where the problem is. The shaft is 1.25 inch and the engine is 50 hp Isuzu. I am using the prop designed for my set up but just in case tried a Campbell Sailing prop which is thin bladed and still the same problem of too hot a stuffing box.

... thanks in advance...

[Nemo55]

Well speaking from a purely mechanical point of view (land vehicles) it could be a number of things,,sounds like to create that kind of excessive heat the stuffing box is taking a strain it shouldn't,,or the prop shaft is oscillating maybe.
i'd say what you need is a heat sensor gun which can localy target an area,,use this to read the temp along the drive line,,bearings, seals, etc,,,then get yourself a timing light and hook it up to the motor and shine it along the shaft and see if you getting any variation in longitudinal and lateral travel. Best of luck,,

[Blue Stocking]

could be the stuffing box adjustment, or clearances.
Describe the stuffing box, or post photos.

[Maine Sail]

Could be...

Improper packing size
Continuous ring as opposed to individual cut rings
Improperly cut rings
Improperly installed rings
Ring cuts not staggered
Overtightened and improperly cut/installed rings
Too many rings in box
Improper alignment
Clogged shaft log

These boxes are about as simple as it gets and in many years of doing this I have never seen a "defective bronze stuffing box" except for one that had been dropped and the threads mashed.

[sy_gilana]

Originally Posted by Maine Sail

Could be...

Improper packing size
Continuous ring as opposed to individual cut rings
Improperly cut rings
Improperly installed rings
Ring cuts not staggered
Overtightened and improperly cut/installed rings
Too many rings in box
Improper alignment
Clogged shaft log

These boxes are about as simple as it gets and in many years of doing this I have never seen a "defective bronze stuffing box" except for one that had been dropped and the threads mashed.

+1 for this answer.
There is only one correct way to pack.
You must only tighten while the shaft is turning, and give it time, let it pour out, and sloooowly tighten then give it time. A job well done could last 25 years...

[bcguy]

Thanks for the replies... all very helpful. I put a feeler gauge between the shaft and cap (where the shaft enters the cap aft of the tranny) and found it would not slip between at all on one side and easily fit to the point of lopsided on the other. I am sure this is part of the problem.

...thanks again ...

[S/V Alchemy]

By "cap", you mean "coupler"?

If you have that kind of play, that is likely imparting a nasty wobble to the shaft and is likely shortening the life of your cutlass bearing, to boot.

Sounds like a decent alignment, plus a repack to address the wear already done to the packing, will help solve the issue.

How do you like your Swain design?