Re: 2QM20 stiff transmission shifting
I've got the same engine and same trans. I agree with you, start with the cable. Hopefully that will be the culprit.
While you are down there operate the shifter, with the cable disconnected. Youll need some leverage but it should click firmly into forward, neutral and reverse.
Assuming that you have the Kanazaki/Hurth transmission remember that it requires ATF not motor oil. And unfortunately this transmission also requires that you shift into reverse while sailing so ... it's a bit of a drag ... so to speak ... :-)
1977 Bristol 29.9