My 1998 2800 scr had an aftermarket hour meter that I didn't trust when I bought the boat. It didn't have a MPI or computer either. was the last of the carb engines for that model.
Anyway.. I researched and found you can pull the engine hours off the ignition module. You need an old school scan reader but it work. Hours were accurate and it showed hours by RPM ranges which was helpful. I found a local mechanic who did it for me.
If you have the thunderbolt IV ignition it should work. Need a mechanic with scan tool and wire adapters.
scan tool link Rinda Technologies - MerCruiser Scan Tool Spec.
Personally I didn't want to buy the boat unless I could verify the engine hours.
ended up being correct at 369 hours but it could have been 1400 for all I know.
best to make sure in my opinion.