Upon inspection of the existing shaft (which connects to the coupling) the key sizes does not match and my cutless bearing is shot.
I made it to South Texas late Sunday night to be ready first thing this morning to run grab the coupling and deliver it for installation. The image left is of the old cutless bearing that you can tell looks worn out. The shaft runs through this bearing just before the propeller, the grooves that you see in the rubber section allow water to run past the shaft keeping it lubricated and in place while the propeller is turning. Image on the right is the new cutless bearing installed showing the difference in the wear.
Every time I take the boat out of the water I will check this bearing, it is an easy test. Grab hold of the shaft between the bearing and the propeller and try to move the shaft back-and-forth, there should be very little, to no play, in the shaft.
The cutless bearing plays another important role, the shaft outside of the boat is held in alignment with the transmission inside the boat through this bearing. When the bearing wears out that changes the alignment of the shaft and can begin to wear in to the hull of the boat where the shaft enters the boat.
This is a part that costs less than $30 for this small of a boat and can save hundreds, if not thousands, of dollars in damage. The problem with all of the below waterline stuff is that you won’t see the problem until it’s taken out of the water in another year! I’m fixing everything I can this round so I can go about 18 months until it’s next haul … when it’s cooler outside .
Since I have access to a machine shop in Rockport, TX (KELMCO Machine and Manufacturing) we have decided to make a new shaft that will have the correct key fittings. After a trip to Corpus to pick up the 3/4? stainless steel rod and some key stock we get to work this evening.
These machines are awesome, I can see why so many guys are drawn to massive power tools like these. To see a regular round rod of stainless steel turn in to a piece of machinery that will turn the propeller of my boat was a blast. Mike Kelm of Kelmco Manufacturing Inc. took the time to make sure I understood what was being made and 
how to figure the tolerances and precision for this particular part. He also made sure all of the parts fit together correctly, and polished my propeller back down to the brass.
One last lesson for today, zinc! See the little ball between the cutless bearing and the hull of the boat? That is a ball of zinc. Well I learned that salt water is a fantastic conductor and, of course, causes a LOT of corrosion because of it. Well the zinc has even high conductive properties and will divert a great deal of the corrosion to this ball of zinc and slow down the corrosion process on the more vital parts sitting directly in the salt water. For about $8 for this size zinc it is another great investment, although I know it will need to be replaced in 18 months on her next haul out.
Great photos of the cutlass bearing, that is very helpful. I am pulling my sailboat out of the water for a bottom paint next week and will be changing the cutlass bearing as well.
Can you explain how you removed the shaft ? I imagine you unbolted it from the transmission and removed that fitting/joint that couples it to the transmission ? Then is it as simple as pulling it out by grabbing the propellor and yanking ? How about installing the new shaft, use grease to get thru the cutlass or how ?
Dave
Hey Dave, thanks for the comment! On removing the shaft I had to cut the shaft coupling in half because it was rusted beyond recognition. We tried using heat to expand it with no success. Once the shaft coupling was removed it was as easy as pulling the shaft from the propeller end.
Putting the shaft back in was just as easy, no grease or anything. Just one person inside to guide the shaft in to location and me outside with a rubber mallet to tap it in completely.
I was surprised at how simple the installation was.