What I "can tell" from your pics.
You have an older "Force" motor.
Force was born when Chrysler Marine went bankrupt and Bayliner (the boat company) bought the engine division and re-named it US Marine. They built motors with the parts they got from Chrysler and packaged the US Marine/Force motors with their boats as a "ready to go" deal.
A couple years after that transpired, Brunswick (who owns Mercury) bought out Bayliner and gave the US Marine motor division to Mercury.
Merc dropped the US Marine name and started producing Force motors which were still primarily Chrysler's (mechanically). As they started running out of Chrysler parts they started cobbling in discontinued Mercury parts (initially from motors that were built in the 70's) so you got a "franken-motor" that was part Chrysler and part Merc.
Towards the end there was a few Force models that were pretty much Merc parts, but not modern or the same as what they were using on "real Merc's".
Looking at your pics there appears to be some components that are outright missing (the starter is gone), and the cost of the starter alone is probably more than the value of the motor.
Not trying to discourage you but if it was me I would scrap the motor and get something else. These motors had almost no redeeming qualities, they were a disposable motor from the start (most models), parts are getting harder to find (and impossible for some models) and a nightmare in some cases to try and source.
As an example, in the early 90's there were over 30 "variations" of the 90 horse and not all parts were swapable even between the same horsepower (models) produced in the same year.
You could spend a grand getting this thing to run only to be the owner of a 300 dollar motor.
But that's just my opinion and probably worth what it cost you
