It won't go in easily

[Portland Billy]

The starboard outdrive on my Sealine (AD41s) won't go into gear cleanly - ie it 'hunts' in and out when first put into gear. However when the revs are increased it suddenly jumps into gear and then acts normally until the next bout of maneouvring.
Is this an adjustment problem - or am I looking at boat out of the water and major outdrive open wallet surgery ?
She will be coming out of the water at the end of October for the usual annual work-over, so maybe it can wait until then if I'm not causing undue further damage.

 

[spannerman]

First check you are getting full throw on the shift cable, if it is then the cone is glazed or worn, which means top section off and stripping to check/replace the cone.