1964 evinrude 18 hp fastwin needs overhaul

[BCOWANWHEELS]

HEY EVERYBODY,I just bought a 1964 fastwin model 18402d and its stuck ! I,am guessing a siezed piston or pistons, got some engine oil soaking in the cylinders now with plug openning facing up. anyway in the worse case sinerio of i have to bore the block could I make this a 25 hp engine ? IF SO WHAT ALL PARTS WOULD i NEED and where can i get them ? also a model number would make getting parts alot easier. all help and tips are greatly appreciated.
I sure would hate to see this go to waste.
bob in tn.

[Elton Smith]

The only part you will need to make it a 25 is a new carb main jet.The bore and stroke for that engine is the same as a 25.I have taken the head off those and used a block of wood and a hammer to get them unstuck.I use marval mystry oil.

[BCOWANWHEELS]

THANKS MR SMITH, FROM READING ON THE INTERNET I THOUGHT THESE PARTS WAS DIFFERENT ALSO.
HEAD,PISTONS,INTAKE AND CARB. I SURE HOPE ALL I HAVE TO DO IS THE MAIN JET,SURE WOULD BE A BLESSING. I PULLED THE PLUGS AND THEY LOOK PERFECT. something tells me the old fella I got it from let the impeller go bad on him and it got it hot. I havent pulled the head off yet, got it soaking till I can get time to do it.
regards
bob in tn.

sorry about the caps but my eyes are getting bad and its hard to see..