manual override has ceased up on tilt/trim unit

i have a 90 yamaha 4 stroke and the motor on the tilt/trim went out last week. cost to replace is $900.00 but my question is the tech told me my manual override screw had ceased and he didn't want to try and fix it because "it might open a costly can of worms " . I'm not quite sure what he's talking about...could it be real bad and if so why ??? I'm not too comfortable about not being able to get the motor up in the event the motor craps out again.
any advise would be greatly appreicated

thanx

Congratulations to the world of Yamaha and expensive repairs. I know,may be true, but not funny. As far as the manual relief valve being seized he may want to try nothing hotter than mapp gas and an impact driver to get it to free up. That may work but he is correct in that if he shears it while trying to remove it and has heated it to the point that the oring seal has melted then you have that "can of worm" he is talking about. See if he can source a less expensive trim motor for you.

Pappy
if the screw is sheared off and the oring is melted, how hard is it to fix (Obviously, I'm not a mechanic. My wife came into our marriage with more tools than I,But I had alot more fishing poles)
I really need the peace of mind knowing theres another option to get the motor up.

Thanx
Bill

If that happens then the only option is to drill out the valve assembly which will effectively ruin the complete housing.