Need help separating shaft coupling

[tomgrigsby]

I have a 70 Hunter 30 with a Yanmar 3GMD. Failed in my first attempt to check engine alignment. I was able to easily remove all four bolts in the coupling, but the two halves would not separate. Looking for recommendations for good method to separate the halves. I made a few cursory attempts to drive them apart but didn't apply much force and quit while nothing was damaged and I can still go sailing Sunday (our first Pagan River race of the year).

 

[jtm]

shoot it up with "PB Blaster" for a few days.

 

[Alan]

With two equal weight hammers strike opposite sides of the coupling at the side time. This procedure can break almost any tight fitting loose and not transfer any undo load to the shaft. The trick is to make the strikes simultaneous.

 

[Ken13559]

could it be your packing gland is tight? what about barnacles on shaft? maybe you were trying to push them into the cutlass? it shouldn't be difficult to split the two couplings.

 

[tomgrigsby]

Thanks for the advice, I'll give the PB Blaster a try first, then go after force. Yes, I too though they should just come right apart, but there wasn't the slightest movement whatsoever, so the halves are clearly coupled together. I wondered if there is some sort of centering flange or something contributing to the fusion.