Shaft Coupling Removal and Loose shaft Nut

[Vincentc]

The most difficult part of removing the coupling was the cotter pin. The hole in the coupling was about 3/8" aft of the pin. With the PSS shaft seal, the shaft does not go back very far and to see the cotter pin very well I had to use a mirror to see what I was doing. Retrieving the pin was time consuming and frustrating.
I finally was able to pull it out. The nut on the end of the shaft was loose and I removed it by hand. Using Kroil penetrating oil and a threaded puller, it took just a few taps with a hammer for the coupling to slide off.
As I understand it the the taper is supposed to carry the load and the nut is there for safety; however, isn't the nut supposed to be tight? It's a 1 3/4" tapered shaft. Also is it cause for concern that the coupling is so far back on the shaft that the cotter pin is forward of the hole in the coupling?
Thanks
Vincent

 

[Boatsb]

Who fitted the coupling?

When we replace them it's all sent to the shop to be matched and fitted? Either someone switched it out or it was poorly fitted.

 

[Vincentc]

Good question regarding who previously fitted the coupling. It was apparently done before I bought the boat in 2008. What might have been done to a boat before you owned it makes me think about the Jimmy Buffett song "the stories we(it) could tell" This is the first time that the coupling has been separated since then.
I took the coupling to the machinist and he advised that the coupling had been mistreated and he would rework it. He did not think I needed to pull the shaft and machine it as well.
I've purchased a SS lock-nut with nylon insert to use in place of the nut with cotter pin arrangement.
I plan on using an anti-seize compound on the shaft threads, and I recall reading that the nut should be torqued to about 100 ft/lbs.
Does that sound OK?
Thanks
Vincent