Suzuki DF150, year 2011
Abt. 250 hours.

The whole bottom unit was changed after hitting an underwater rock in cruising speed.
Not sure how this can be related to the problem, but after the service the engines revs down about 300 rpm when I trim the engine down.
As soon as I let go of the button the rpm goes back up.
The speed and rpm go down immediately when I hit the trim button.
Nothing happens to the rpm when trimming up, that works just as it should.

Any ideas what could be the problem?