Installing Coupling on Shaft

[H2O]

Now I need tips on how to reinstall the coupling onto the shaft. Removal was as smooth as butter, thanks 8122!

[DanielC]

I have not done this, but I would try this. First, make sure the inside of the coupling is clean. Heat it up in an oven to about 300 degrees. Put a light film of grease on the shaft. Then put the two pieces together. Make sure the setscrew holes are aligned properly. You might need to gently hammer on the shaft to get it to go all the way into the coupling.

[8122pbrainard]

H2O, Glad it worked and glad to help. Daniel has got it with the oven but I'd kick it up to 475 . Some will even pack dry ice on the shaft end inside the boat. I've never found it needed. A lot depends on how tight the fit is. Did you measure the fit? It should be .000 to a max of -.001". You never answered why you had to pull the shaft. If you are putting in a new shaft, the measuring of the fit to the coupling is very important.

[JUST-IN-TIME]

do not grease tappered shafts

[8122pbrainard]

do not grease tappered shafts

??? It's not a tapered shaft. We're discussing shrink to fit straight shafts.

Here's Removing the coupling thread: http://www.planetnautique.com/index....ic&t=12730

[JUST-IN-TIME]

u sure thats not tapered on the shaft?

[H2O]

Trying to chase down a very slight vibration. Shaft is true so the coupling goes back on the original shaft. Once the coupling is hot is it better to tap the coupling onto the shaft or to tap on the end of the shaft to seat the shaft into the coupling? Or will 475* expand the coupling enough that it will slide onto the shaft by hand? Never Seize on shaft?

[DanielC]

Slight vibrations can drive you nuts trying to find them. First question, are you sure it is not the propeller? Really sure? Is your shaft alignment right on? Does the shaft have a very slight bend in it?
Are the tracking fins in good shape, and aligned with each other?
Sometimes a propeller can run good on one boat, and not on another. Try to eliminate the other possibilities.
I would install the coupling on to the transmission, and then quickly install the shaft into the coupling, with a gentle tapping as necessary, protecting the end of the shaft with a block of wood. I am leaning to avoiding any thing that lubes the shaft. Make sure the set screw holes line up.

[djbartholomew]

I had a virbration one time that wasn't real bad, but I knew that if I didn't find it would cause trans problems down the road, so after a week or two of checking all other sorces I finaly bought a new prop, the old one had no nicks or signs of hitting any thing (was my last option) really thought that I was buying a new prop for no reason, but you should have a spare prop. The prop was the problem, I don't know why, but it was.

[8122pbrainard]

The 475 will expand the coupling enough so it will slide on the shaft and is the concept of the shrink to fit. I wouldn't bolt the coupling to the trans half - it may cool down too much. Clamp off the shaft to the strut with a block of wood so it doesn't slide back on you. The coupling should slid on easy. Have a hammer handy just in case some light tapping is needed also to tap the key in place after the coupling is on the shaft. Snug up the set screws but don't fully tighten them until the coupling is cool. Don't put any anti seize or grease on the shaft. The idea of the shrink to fit is to get as close to a solid fit as possible. You do not want any movement between the coupling and the shaft.

How did you check the shaft for straightness? The best way is with the shaft set in V blocks on a surface plate and with a dial indicator. Most shaft vibration problems are from bends aft of the strut.

[8122pbrainard]

u sure thats not tapered on the shaft?

JIT,
Yes, older shafts are straight and not tapered. The tapered coupling to shaft came after the V drives were out a couple years. It was discovered the PITA problem of V drive shaft removal with very little space to work in. Some will even pull the engine as they find it easier to pull the shaft and coupling together forward through the log!

Next time you go to one of your schools, maybe you can suggest the topic to whoever is teaching the class. It may not be bad to at least discuss it. We all don't have new boats! I'm surprised you haven't run into a straight shaft yet.

[JUST-IN-TIME]

nope, cuz maybe in cali everybody owns new
i have worked on tons of older outboards and i/o's but old v or direct drives are not around are parts

good to know

i will bring that up at my next class!!!