Hy Barcho, welcome, having no idea of your mechanical knowledge or skill, I would suggest some investigation of your engines condition before making any decisions about replacing/rebuilding your engine. Remove the engines spark plugs and "read" them for their condition, I'm sure googling "spark plugs, checking" or something similar will yield picture and descriptions. A compression test will also tell you about general engine condition. Do some investigation so you have more information. A word about engine rebuilding, if you have a shop rebuild your particular engine you will pay for their time by their hourly rate, if you buy an exchange engine you pay a flat price for the engine and you give them your old engine as a "core" to be rebuilt, if you don't have a "core" you will have to pay an extra fee. I doubt anyone will have an exchange program for these old engines, just trying to educate. Good luck with your project.
