Splitting drive shaft from engine flange

[Pagetslady]

Has anybody any experience of removing the prop shaft from the coupling flange on a Yanmar 56 hp. The flange is removed from the gearbox flange by removing four bolts and is easily drawn back, my question is are there two nuts on the end of the shaft taper or just one, I have not seen this arrangement yet a friend has explained how far he has managed to get previously but doesn't think there are two nuts, but has not been able to get the flange off the shaft, Is the shaft tapered? Any help will be appreciated.
The engine is in a Sun Odyssey 40.
Mike

 

[vyv_cox]

Have a look at my website, lots of examples there and a good method for flange removal. Unusual to have a taper at the drive end, a straight is far more common.

 

[Mistroma]

Has anybody any experience of removing the prop shaft from the coupling flange on a Yanmar 56 hp. The flange is removed from the gearbox flange by removing four bolts and is easily drawn back, my question is are there two nuts on the end of the shaft taper or just one, I have not seen this arrangement yet a friend has explained how far he has managed to get previously but doesn't think there are two nuts, but has not been able to get the flange off the shaft, Is the shaft tapered? Any help will be appreciated.
The engine is in a Sun Odyssey 40.
Mike

Long time since I replaced the seal, I was in a rush and did not have the correct puller. I made the mistake of getting a "marine engineer" in (almost unheard of for me to let others work on my boat).

a) Several delays before he turned up, probably quicker to have just done it myself
b) He didn't have the correct tool either

He just did what I would have done. i.e. Use a large socket or similar and longer bolts to push the flange off the shaft. I caught him banging it with a hammer after trying to press it apart, sending side shocks into the gearbox thrust bearing.

He wasn't pleased when I stopped him and we used some heat and more pressure.

It was on a Yanmar 4JH4AE and as far as I remember there was only one nut on the end of the shaft.
it was quite tight but did come off using the makeshift tool.

Try the same approach

1) Disconnect 4 flange bolts
2) Lock the prop. and loosen the interior shaft nut
3) Fit a billet or something else that's round and fits over the end of the loosened nut (or shaft)
4) Draw flange back together (you will probably need to buy some longer bolts)
5) Use a bit of heat along with the pressure

I can't remember if there's enough thread to just loosen the nut or if it need to come off completely (increasing chance of thread damage when applying pressure to the shaft.

I only remember one nut but is was several years ago.

EDIT: I see Vyv beat me to it. I'm certain his web-site will suggest a similar approach but have more detail and perhaps some alternatives.

 

[Pagetslady]

Thank you both I will look at Vyv’s web site I do know that this method has been tried but was not able to shift it he was worried about using heat because fuel tanks nearby perhaps using heat gun on flange maybe freeze the shaft with dry ice any way I will give it a go next week. Mike

 

[crown22]

Hello Mike probably not relevant but my R&D gearbox coupling was fastened to the propshaft with two allen grub screws on top of each other which located into a crater in the propshaft. Shaft not tapered. Bit of a pain to remove them both before using a
puller to remove R&D before removing stuffing box and hose seal for overhaul.Regards Stephen Yacht Rhiannon

 

[Pagetslady]

Hi Stephen thank you for your answer,
Mike