1984 Mercury Black Max 150hp questions !

[Heywire77]

I just purchased a 1984 Mercury black max 150hp outboard from a person I knew that had mainly spent most of its life in the garage , runs great and has even good compression on all cylinders ! My question are my boat is rated for a 200hp I have a 1997 Ranger 518svs Comanche I'm installing it on and I would like to up the horsepower some more ! Any tips would be great also I have been a mechanic for over 20 years mainly automotive and small engine and the last 7 years has been outboards and inboards mainly just servicing them and repairs , I was never into souping up motors or anything so could use some help in this area maybe some tricks for this motor ! I have heard afew things about having the heads shaved and running higher octane gas if so how much increase in horsepower could I gain guessing ? Also I heard something about the reeds if anyone knows anything about this please tell ! Also I seen somewhere that there was a bulletin years ago for the jets on my carbs from a 82 jet to a 84 jets anyone heard anything about this and were to find them or would they come in the standard carb rebuilt kits ? Also what is actually the difference in the 150hp and the 200hp that year because I have looked up parts and it shows a lot of the parts are the same ? Thanks for any help

 

[Dukedog]

if '84 150 its gonna be a 2.0 motor.. not a good candidate ta hot rod.. especially ona Ranger.. your gonna get a lotta "do this and do that" but most will be jus plain 'ole bs. for your rig....ie: there's not a 2.0 150 production motor made with those size mains!

if tha motor idles/runs good and is healthy with good compression I wouldn't touch it.. jus know that its not gonna be a barn burner on tha Ranger.. ya gonna need ta do some experimentation with props and set up ta maximize your performance...jmo

difference is in tha block size, cylinder material, porting, front half, reed plate, carbs, heads jus ta name some...

jan... I've been buildin' stem windin' V6 Merc/Mariner's only up ta 300+ hp since tha first one hit tha public market in '76.......

 

[Faztbullet]

Like Duke posted not much to do to this motor, if you want a 200hp need to buy a 200hp. The heads shaved will add 2-4 hp,reeds adds nothing and the jet change was for 200hp engines

 

[Heywire77]

I sold it and purchased a Johnson 235hp outboard .