Had the same on a new ball-valve sea cock I installed for the head
2-3 years later it was acting funny
. Not sure what was wrong but all of a sudden I got a recall
notice from Groco. They used some cheap
Chinese SS in the internal and the handle separated from the ball. Kind of felt normal when I open and closed it as there was some friction. In reality nothing happened, the ball was rusted stuck in the half-ass position.
Groco or whoever made those thing refused to pay for haul-out, but they sent me a new and improved model seacock.
Glad it did not sink my boat as I always close the non-essential seacocks between cruises.