Engine is the same from 88 to 89.----Carburetors are simple ( crude ) devices that respond to the air flowing through them.-----If there are issues within the engine then swapping / fiddling with carburetors is a waste of time.
Your local machine shop / blacksmith / highschool could make that bushing.----Strange that this bushing is worn as there is no motion when forward is engaged.
Post your compression numbers.----And when starting do you advance the throttle to the neutral stop ?----Best to ignore the start mark on the steering handle.
Some simple trouble shooting will quickly determine the issue.----But it can be difficult to convince folks that this is the money / time saving approach.
Some sales brochures say----" world class boats "-----Did not appear to be a fact on mine.-----All rotten plywood transom and stringers that needed replacement.
I think you need to trouble shoot this motor.----Post the compression numbers.----There is more to it than an adjustable idle mixture on a carburetor!----Sounds to me the 89 carburetors did not fix the issue.-----Then you became the proud owner !!
