shaft coupling

[alcodiesel]

Turns out the key was brass. The mechanic said that it usually is stainless. The brass said it all- as it was scrunched. Shaft is fine.

He pulled the shaft, installed the new cutless, and today the stuffing box and split coupler.

Besides a PO shifting at full throttle could the brass key be scrunched up by a misalignment?

[Dave Neptune]

My opinion

Bill, yes I think it would. If the shaft "moves" at all in the coupling because of the misalignment the "torque" against the "key" would oscillate from end to end ever be it so slightly. The brass is far softer and much more malleable than steel or stainless steel and would eventually break down, mostly because the brass is not strong enough in the first place. A set screw will not aid much in holding because it is at a single point. A split coupling would reduce this quite a bit but because of clamping pressure however it may indeed still break down. The "key" takes the torque and needs to be strong enough to resist.

Look at older OB lower units. The gears were protected by the "key way" or aptly named "shear pin" incase of an over revving gear shift or a prop strike.

Dave Neptune

[alcodiesel]

Thanks Dave. We're going to check alignment.

[ndutton]

In my experience shaft keys on sailboat auxiliaries were always made of the same material as the shaft. That is, not intended as shear protection.

[alcodiesel]

A split coupler and stainless key was installed and the engine was out of alignment as we suspected. New stuffing box and tube, cutless, alignment done.
Next rebuild the 45 year old Ericson standpipe exhaust, er, I should say build new one.
All below waterline hoses replaced. Steering checked out ok.

I plan this is the boat to take me to the wire then I'll leave it to the kids so it can molder away in the slip- although they both know how to sail. But that will not be my problem!

She should be back in the water soon. Yaaa! cause the wind is great in the winter here in southern Chesapeake Bay and I know how to dress for the cold.