newbie with merc questions

[fairchildm]

ok guys i just bought my first bass boat a 93' ranger 482vs with a mercury 175 that the ?powerhead? was changed and is now a 200 with only 30 hours on it or so he says. found a few number on the motor that i googled but didn't seem to come back as my motor serial number just part numbers. any help would be appreciated, its a 2 stroke right? i was told to mix it 50:1 is this correct? do i need to add any additives to the fuel? and if so what kind? thanks again. YES i know i shouldve maybe done more research before i bought but it was a great deal on a nice boat. did compression test there and it was right on.

[Fish.Team.Rose]

Do you know for 100% sure the oil injection has been eliminated?

[fairchildm]

yeah pretty sure. there is no oil reservoir or no oil fill on the engine.

[EuropeanAM]

Good idea to provide the serial number from the Transom Bracket, and the serial number you found on the powerhead.

Also a good idea to provide a couple pictures of the powerhead (especially a FRONT, and a PORT SIDE view).